HERO system has been around since 1981 without being tied to any massively-popular IP. Sure, the Champions Universe is beloved by many, but it's not a feature of the system. The system is the feature of the system.
Sure, it's not D&D popular, but nothing is.
The problem I have with what I believe you're saying is that it is a matter of record that the TSR business practices that you're citing as successful were, in fact, not. FR and DL have indeed proven very profitable IP. Planescape, Al-Qadim, Birthright, and Mystara have not. As others have pointed out, TSR was also pumping out ginormous amounts of player-centric crunch books. TSR's insistence on continually creating new settings and adventures was one of the reasons they went belly-up.
FR and DL have been successful becasue they are interesting worlds that were lucky enough to have both good design teams and talented authors pumping out novels. IMO, R.A. Salvatore and Weis/Hickman are the prime movers behind the popularity of their corresponding settings.
And if the recent downturn in the RPG industry has shown anything, it's that IP alone will not make a game successful. Plenty of RPGs have used licensed settings far more popular overall than even FR or DL, and it didn't automatically result in strong sales. Plenty of RPGs tied to popular IP have bombed. E.g., LOTR is probably the most popular fantasy setting on earth, but I don't remember seeing a single Decipher LOTR RPG event on the roster for this year's GenCon. Or, heck... the most recent Marvel or DC RPGs, anyone? I didn't think so.
The simple fact is, the current business practices of WotC that you are lamenting are far more sound strategically than anything TSR ever did. The vast diversity of settings is there for people who want it, thanks to the OGL: Midnight, Kalamar, Scarred Lands, Arcanis, Oathbound, etc.
And where are the great modules? All over the place: WotC, Necromancer, Atlas, Goodman, Green Ronin, Malhavoc... You just can't get all nostalgic about them yet.