What if?
MtG never exists - I'm going to take that to mean that Richard Garfield never proposes his idea for gamer crack to Peter Adkinson. Wizards of the Coast continues to be a small RPG publisher, publishing things like Atlas Games does today, instead of becoming the CCG juggernaut that it has become. Eventually someone else will get the idea to do a CCG, but I'll punt it down the road for, say, 5 years - CCGs don't hit the market until say 1998 or 1999. Maybe Nintendo harkens back to its pre-video game days and comes up with Pokemon without the CCG craze in the US to propel it along.
Anyway, TSR doesn't make the disastrous investments into collectable games that they couldn't handle - no Spellfire, no Blood Wars and especially no Dragon Dice. The company manages to float along, coming out with new settings and pushing gaming novels. They continue to do no market research on any product that they choose to put out and continue to invest heavily in licenses that the owner of the company has a vested interest in promoting but do not have mass appeal (Buck Rogers) as well as new settings to push new novels into the mass market.
TSR also continues to actively resist fans on the Internet who "violate their copyright" by posting fan-written supplements. As the Internet grows in popularity, TSR lawyers hunt down "offenders" by the dozens and send out ominous cease and desist letters. As more fans come to the Internet and see the face of TSR corporate, they become more bitter about the company as a whole. TSR continues to feel that these people are cutting into their revenue stream, and that fan-produced works are taking money out of their pocket. The hostility between the company and the fans never really dies down, despite heroic efforts by some freelancers and internal staff to try to get TSR to come around to a more modern stance on the Internet and the value of the fanbase.
Meanwhile, without MtG, local game stores lose the income that allowed them to limp along during the mid-90s. Following the comic book market collapse, many combined comics/games stores that would have limped along on MtG sales collapse into bankrupcy instead. Many game/hobby stores push more of the Games Workshop line of minis or model trains to keep alive, relegating their orders for RPGs to only the "most popular" - Dungeons and Dragons and World of Darkness - with a smattering of other popular RPGs like GURPS, Palladium, etc. based on what the owners like to play.
As the late 90s approach, TSR sees the success of Games Workshop in the market and attempts to follow suit with their own line of minis. This is widely regarded as a disaster for the company as hundreds of thousands of dollars are spent producing miniatures for a wargame that doesn't even begin to compete with Games Workshop's Warhammer juggernaut among the "casual" wargamers, and can't find its own niche other than being "not Warhammer". TSR files for bankrupcy and restructuring prior to 2000, just as the CCG market is beginning to explode with Topps gaining the license to distribute Nintendo's popular Pokemon game imported from Japan.
Due to poor decisions by TSR management and ownership, TSR is back in bankrupcy within 2 years. Plans for a "AD&D Third Edition" never pan out because the company sunk so much money into its own collectable card game. This time, the company is gutted by its creditors and its properties are sold to pay back bills. "D&D" is the biggest property and all of it (including the gameworlds) is sold in one big chunk to a popular video game company that had dealings with TSR (whoever Bioware might be in this scenario, probably). The only D&D gameworld that is treated differently is Dragonlance, which a company formed by Margaret Weis and Tracey Hickman is able to require through some legal gymnastics. They continue to produce novels and occasional game supplements that are "compatible with AD&D". The non-D&D games are sold off peicemeal to companies and individuals who can pony up the cash for them - Metamorphasis Alpha is bought by Jim Ward, while the rest are snapped up by other companies fairly cheaply.
The rights holder for D&D has no interest in publishing books, and licenses the game out for a fee to anyone who has the money to pay for it. White Wolf snaps up the offer, gets ahold of the manuscript for "AD&D Third Edition" and hires some former TSR writers to finish tweaking the system. "AD&D Third Edition" is rushed out the door by 2002 and is moderately successful. By this point, however, the fanbase is heavily divided. Many fans alienated by TSRs actions refuse to come back to D&D. Fans of "old school" D&D refuse to look at anything published by White Wolf because of their angsty goth stereotype. And folks who might be interested in the "new" D&D get turned off by the actual ruleset - something that looks more like 2nd Edition AD&D with Skills and Powers rules than what 3rd edition turned out to be. White Wolf has a larger success with the game than they were hoping for, but it doesn't rise to the level of what 3rd edition managed here.
Present day, White Wolf controls the two top RPG games in the business and is the "leader" of a market that is much smaller than it could be. Fewer independent retailers exist and so the main places to find RPG games for sale are at bookstores and online. What remains of the hobby market is dominated by miniature gams and collectable card games - and new collectible miniature games are just starting to push into the market. Fan communities exist each supporting their own version of AD&D - 1e, 2e or 3e, and neither White Wolf nor Bioware is as concerned about killing them as TSR was so they function fairly well. Without the "OGL" push in 2000, PDF publishing for RPGs isn't as far along as it is today.
That's about it - sorry that it seems mostly like doom and gloom, but I remember what game stores were like from 1992-1998 far too well to think that it would have been better without MtG there to keep the industry afloat.