The one time an I7 game’s gotten too large to be compiled before, it was due to a compiler bug rather than an intrinsic limitation. (And I believe that bug is gone now?)
There are no practical limits where the game is too big to compile or run. You may find situations where, as the game grows, it starts running more slowly (particularly on mobile devices) and perhaps you need to think about that. But this is not what you should be worrying about when you start designing a game.