Ah that makes a lot more sense, that was a bit of random-looking claim!
Man SAGA was quite a thing. I loved the system in a lot of ways, but I dunno if anyone really loved the later-Dragonlance setting.
Poor old Birthright. If that had come out in like, 1990 or 1991 instead of 1995, I think that could have been absolutely huge. By 1995 White Wolf and other companies were so huge though that "alternative" AD&D settings that weren't deeply zeitgeist-y (Planescape was perfect mid-1990s zeitgeist and Dark Sun was pretty good on that too) weren't going to cut it.
I think that's one thing that sometimes gets lost in the criticism of TSR. WotC has never faced an environment as challenging or dynamic as TSR did. They fucked up in loads of ways, TSR, but at the same time, the seas they were sailing were massively choppier. White Wolf and other people put huge pressure on TSR by coming up with RPGs that really spoke to a new generation of players in a way AD&D was literally never going to. TSR was stuck on the back foot because 2E was one of the last of an older generation of RPGs, design-wise, something only a new edition could really have fixed, and that itself would have caused big problems in such a turbulent landscape.
WotC bought TSR at exactly the right time and frankly 3E got pretty lucky, because White Wolf had by then lost several key creatives (to various weird spats and so on), and was kind of misfiring. VtR and the nWoD books were more elegant and well-designed (both in setting and rules) than the oWoD, but they didn't capture the spirit of the age in the same way, and they split the audience at a crucial time (I knew a lot of people who just stuck with VtM and so on). A number of other publishers seemed to have big problems of their own, or made really bad decisions (R Talsorian, for example, and FASA), all in part because of our good friend Magic: The Gathering, which was part of the extremely choppy waters, and lead to a lot of bad decisions from others (including doubling down on Dragon Dice from TSR).
So going into the 2000s, WotC had calmer seas, and could release a version of D&D that didn't feel hopelessly dated. The OGL was cherry-on-top genius and I take my hat off to Dancey and the others who came up with that, because it basically steamrolled non-d20 games by strongly encouraging people to try and make something compatible with 3E and get a piece of that pie. RPG stores which used to be diverse as hell, with AD&D stuff being like 20% of what they carried, tops, over a year or three became 50-60% D&D 3E and d20 products. Given that virtually all the real competition had already self-sabotaged, it was easy win, and I think WotC can be over-congratulated for it. A lot of what they did was extremely crude, like just dumping huge numbers of splatbooks 24-7 (and I'm sure they had plenty of bad sellers in there, relatively speaking).
I loved SAGA, but I'm pretty sure 3rd edition Dragonlance ended up being more popular. SAGA Dragonlance was effectively "Spellplagued Realms", ie highly divisive, yet with some interesting stuff in there.
Post War of Souls was basically 5E Realms -the interesting stuff from the SAGA years kept, plus the 2nd edition stuff you liked back in.
SAGA definitely had the best Bestiary of all time, though. And the simple stats meant the era was golden for fluff.