Maybe I'm misreading the article but it sounds like even when just copying data from cartridge to vram there isn't enough time to get 60fps, no matter how fast your emulator hardware is.

However, I guess that is a problem for arbitrary video where you have to be able to completely swap out the tile map on each frame (actually 2x/frame). For a GB game you could only swap the tiles/sprites that have actually updated and send over info what to redraw.

So potentially possible I guess? Someone should do the instruction count / bus bandwidth math.