I would claim there is no direct competition between 2D and 3D games. Each have their own advantages and disadvantages, and people can have various of reasons for choosing one over the other.
I prefer to work with 2D, as I feel it gives you more freedom in creativity (not to mention it is
easier). Some of the things you do in a 2D game might be weird or not look good at all in 3D.
To bring an example to the table; I prefer Mario in 2D; or even 2.5D with a "classic" platformer style gameplay.
Mario in 3D is a completely different experience than the 2D, but can still be considered a "type" of platformer genre, but offers a completely different experience than the 2D.
In the end I think it really is up to how you like to play - and type of gameplay.
Some gameplay can be better in 2D than in 3D and vica verca.