Jaeger
That someone better
Seems the OP's vagueness has resulted in two questions being answered:
1: If D&D wasn't released in 1974 - would RPG's be invented anyway?
2: If WotC didn't bail out TSR and they went under - what RPG would have taken D&D's place.
So first, question number one...
1: If D&D wasn't released in 1974 - would RPG's be invented anyway?
Disagree. The early days of the hobby are very well documented.
Not that right place, right time, wasn't a huge factor.
I used to think that argument was BS myself - after all why didn't they publish their version when D&D proved such a hit? Turns out some things are just more complicated and nuanced than that:
One example:
playingattheworld.blogspot.com
There was convergent / parallel discovery going on in the 70's. Some of the hopefuls couldn't get the scratch together that Gygax and co. did to publish. Some had their creators die too early to see things through. And some just said stuff it, and played the more popular and commercially available ruleset rather than going through the hassle of publishing their own.
RPG's are Wargame Derivatives.
And in 20-20 hindsight, we know the intuitive leaps needed to go from the variety of wargames in circulation in the 1970's, to RPG's as we now recognize them.
IMHO - for A "different" RPG to take hold it would have had to be a Fantasy RPG similar to B/X in complexity, and would have had to hit before 1980. So that it would have enough time to build up a player base before videogames start to become a thing...
And I do side with the argument of RPG's being inevitable sometime in the mid to late 1970's.
Also, yes; all current RPG's and storygames are a reaction to D&D in some form.
Now on to question number two...
2: If WotC didn't bail out TSR, and they went under - what RPG would have taken D&D's place.
D&D as the market leader was the beneficiary of "bailouts" because it is better to start with an established IP than trying to build one up on your own.
Sometimes those of us that are into other games can forget how big the D&D 800lb gorilla is. Even in Vampire's WoD heyday, D&D only got outsold when it literally went out of print. As the market leader D&D has been bailed out by $$ at least 3 times from its own mismanagement.
Other RPG game lines went bankrupt in similar circumstances because they do not have the player base to make it worth someone's while to jump in with rescue money beforehand.
RPG's are a niche money making endeavor of a hobby, and D&D has always been an outlier.
WotC had to make internal own-goals of epic proportions to create the environment where an edition of D&D that was briefly but legitimately outsold by a competitor.
And even then the "competitor" was a clone of its previous edition...
Yes. Power hates a vacuum.
The Pathfinder 1e saga has proven that the hobby will gravitate to an alternative if the mainstream game fails to serve.
Even in the TSR heyday there were D&D alternatives like palladium fantasy and countess Fantasy heartbreakers of "D&D done right"...
Even pre-3e there were fantasy games that used d20 roll-high, stat+skill, as their base mechanic.
It may have taken a few years but eventually the hobby would have formed around a new fantasy RPG standard.
It would be interesting to see the ascendency of a fantasy RPG that hewed close to many of the tropes of D&D, but was without the decades of TSR baggage, and lore assumptions would have turned out like.
1: If D&D wasn't released in 1974 - would RPG's be invented anyway?
2: If WotC didn't bail out TSR and they went under - what RPG would have taken D&D's place.
So first, question number one...
1: If D&D wasn't released in 1974 - would RPG's be invented anyway?
I don't even think I could speculate, because I don't think we understand properly other than right-time, right-place why D&D became what it did.
Disagree. The early days of the hobby are very well documented.
Not that right place, right time, wasn't a huge factor.
While there have been people claiming that RPGs were already inevitable before Gygax and Arneson made a deal to create D&D as a product, I think basically all the RPGs that exist have their current shape because of D&D. Be it following in its footsteps or as reactions against its mechanics.
I used to think that argument was BS myself - after all why didn't they publish their version when D&D proved such a hit? Turns out some things are just more complicated and nuanced than that:
One example:

Western Gunfight (1970): the First RPG?
In 1970, a group of UK gamers located in Bristol published the first edition of their Western Gunfight rules, which recorded systems they ...
There was convergent / parallel discovery going on in the 70's. Some of the hopefuls couldn't get the scratch together that Gygax and co. did to publish. Some had their creators die too early to see things through. And some just said stuff it, and played the more popular and commercially available ruleset rather than going through the hassle of publishing their own.
RPG's are Wargame Derivatives.
And in 20-20 hindsight, we know the intuitive leaps needed to go from the variety of wargames in circulation in the 1970's, to RPG's as we now recognize them.
IMHO - for A "different" RPG to take hold it would have had to be a Fantasy RPG similar to B/X in complexity, and would have had to hit before 1980. So that it would have enough time to build up a player base before videogames start to become a thing...
And I do side with the argument of RPG's being inevitable sometime in the mid to late 1970's.
Also, yes; all current RPG's and storygames are a reaction to D&D in some form.
Now on to question number two...
2: If WotC didn't bail out TSR, and they went under - what RPG would have taken D&D's place.
And that's really tough because when you look at the history of D&D there are all kinds of places where TSR "stumbled" early on and throughout its stewardship of the game, so you'd think someone else could have taken over from them. And yet here we are - nearly 50 years later and it's still the king of the hill.
D&D as the market leader was the beneficiary of "bailouts" because it is better to start with an established IP than trying to build one up on your own.
Sometimes those of us that are into other games can forget how big the D&D 800lb gorilla is. Even in Vampire's WoD heyday, D&D only got outsold when it literally went out of print. As the market leader D&D has been bailed out by $$ at least 3 times from its own mismanagement.
Other RPG game lines went bankrupt in similar circumstances because they do not have the player base to make it worth someone's while to jump in with rescue money beforehand.
RPG's are a niche money making endeavor of a hobby, and D&D has always been an outlier.
WotC had to make internal own-goals of epic proportions to create the environment where an edition of D&D that was briefly but legitimately outsold by a competitor.
And even then the "competitor" was a clone of its previous edition...
Also, if TSR had died and no one picked up the D&D mantle, it is absolutely certain that the RPG industry would have continued on. It is not like people suddenly stopped making RPGs when TSR collapsed. To say that there would be no modern RPG landscape without 3E is a bold statement.
Yes. Power hates a vacuum.
The Pathfinder 1e saga has proven that the hobby will gravitate to an alternative if the mainstream game fails to serve.
Even in the TSR heyday there were D&D alternatives like palladium fantasy and countess Fantasy heartbreakers of "D&D done right"...
Even pre-3e there were fantasy games that used d20 roll-high, stat+skill, as their base mechanic.
It may have taken a few years but eventually the hobby would have formed around a new fantasy RPG standard.
It would be interesting to see the ascendency of a fantasy RPG that hewed close to many of the tropes of D&D, but was without the decades of TSR baggage, and lore assumptions would have turned out like.