Quite a few people just simply never were on the ride, or only slightly so.
I started tRPGs in a one-shot in 1980 at my cousin's but that never went anywhere and it's a side of the family I've not even seen since that day.
So... in 82 two things happened. I got the D&D basic set as a birthday gift from my mother. Then maybe a month or so later I had my $5 of allowance money (that's about $50 million in today's dollars, or so it seems some times), walked into a hobby store and bought a "D&D adventure" that was in an odd sized box.
That's how I ended up with my first non-D&D game. As a kid I didn't realize there were other options, but the box to 'Melee' had Conan like art so I bought it. That's also known as 'The Fantasy Trip' - and the next week I was back to get Wizard, and some time later the compiled Fantasy Trip book.
These days that game's direct descendant is called GURPS. "Melee" is to GURPS what 'Chainmail' was to D&D.
Sure I played a little D&D back then, but just about as much Fantasy Trip. Didn't play in a 'campaign' for D&D until 84, and that very quickly ended in an RPG horror story.
There's a lot of different games out there. And having never really been 'pulled into D&D' in a way that stuck, I got to play a whole slew of them over the decades with mostly decent folks.
I've also met quite a few people who've never even played D&D. Until maybe Stranger Things this hobby was so small that even though D&D was the biggest game, that ratio probably wasn't so vast.
AHHH Chainmail... I used to have that as a boxed set. My main experience in gaming is 1st ed, 2nd. The first book I ever bought was the encyclapedia magicka. It was like 60 bucks. ( think of your 5 dollar reference X12). I thought of it as an investment. Over the years I collected all 4 of the books and went on to the spell compendiums, wizards and priests. Together one of the single best collection of work DnD has ever come out with. I got years out of those books. I liked the mini stories that came with the items.
My first game was with a friend I made at summer. He would stay with his grandma in the summer so I would go over for sleepovers and we would drink pop and game all night. Those were the days!!! My first.
Moving to ottawa my books came with me, and I met a new circle of friends. We would have gaming marathons that would run day n nights for weeks on end. I took up GMing then, and at the time had collected every type of dragon I could find.....36 or so...maybe more, and we started an epic dragon campaign, on of my largest dnd campaigns yet. Then 3rd ed came out and well, I broke away from dnd. They changed everything, tried to rewrite every thing.
I then broke off on my own, and decided at 11:11 at night I would create my own world. When I say the time, I had just finished drawing the first draft of my world map... 26 years later I am working on my 3rd and 4rth expansion, with dozens of books still as of yet to be written.
In some ways I owe Dnd. It helped me make friends, develope my creativity and my visualization....all things I cherish today. But when business became more important to the company, I developed my own. It is my sincere hope that one day my system rivals that of Dnd. While may may scoff, or perhaps not, I can honestly say on its own there will things recognizable, but my system is truly its own entity, an expression of how I see the world in fantasy terms.