I'm pretty sure Sphere has a "no propriety use" license, which means you can't sell game or release them with intention to profit.
Though, still say no full-scale games in the terms of RPGs and story-driven platformers have been made, for honest reasons why.
It's hard making a game by yourself to completion!
Nothing wrong with that, just nothing has come forth on the scale of Chrono Trigger, Final Fantasy, Oddworld, Return Fire, Doom, Mario Kart, etc and so on. which is the point that was being made.
You're making some good points (except on excluding KR and Trial and Error here I think! Those had big ambitions and a good amount of work done
Unless KR was the FF6 game somebody was remaking for sphere?
It wouldn't - KR is long, but incomplete, after all.