Personally, i don't think the coding part of game development was not a bottleneck.

Just try to implement, for example, a hexagon-based isometric game. There are no off-the-shelf implementations -- you'll need to redo the pan / zoom / click controls yourself, you'll need to implement the pathfinding, map layers, interface state machine etc etc etc

This is still not an easy task -- to build a somehow complicated game. If you're building a platformer -- sure, that's doable. Strategy/4X/RPG? That's different.