Erm, not all of the Toy Story films were 3D. Infact, I think only the first one was made in 3D.
I believe the original tangent was more that the whole movie series started in 3D and didn't use it in a sequel as a gimmick. (Which, okay, the "Creature" movies used 3D as a gimmick but both the first one and the second one were released in 3D.)
Spy Kids introduced 3D in the 3rd movie (and through the 4th) as a gimmick to increase interest/ticket revenue.
The Harry Potter films adopted 3D late in the franchise, again, to go along with the rising trend, same with the Final Destination films.
The "Creature" and, apparently, the "Journey" movies both started in 3D and continued in 3D.
Only Toy Story's 3rd part was presented in 3D, the first two parts were not. Not originally at least, they were re-released in 3D.
I believe the original tangent was more that the whole movie series started in 3D and didn't use it in a sequel as a gimmick. (Which, okay, the "Creature" movies used 3D as a gimmick but both the first one and the second one were released in 3D.)
Spy Kids introduced 3D in the 3rd movie (and through the 4th) as a gimmick to increase interest/ticket revenue.
The Harry Potter films adopted 3D late in the franchise, again, to go along with the rising trend, same with the Final Destination films.
The "Creature" and, apparently, the "Journey" movies both started in 3D and continued in 3D.
Only Toy Story's 3rd part was presented in 3D, the first two parts were not. Not originally at least, they were re-released in 3D.