Yes, why wouldn't it have been? It's almost exactly the same as the first 3D boom. Graal is 2D... 3D games become more popular and more accessible on PC... everyone says "oh man, Graal needs to be 3D or else it will become obsolete!" Now it's repeating the cycle with mobile gaming, as phones evolved and become more technically efficient. The only difference is that back then there was no proper distribution method for Graal so it was hard for it to "break out."

3D games are not automatically superior to 2D games. Graal moving to the 3D realm is not suddenly going to make it 10x more better, and 3D is not automatically more attractive. Graal is doing just fine the way it is, and in fact is probably doing this well because of it taking advantage of a niche corner of the market. If it were to generalize itself and become like all the other games it's suddenly going to be competing with other products that do a much better job at it.

So? Stefan was also pretty dedicated to his 3D versions of Graal... and he ended up with nothing after years of neglecting the 2D version of Graal in favor of the 3D version.