>>713800670 (OP)Graphics are only one thing to optimize.
A skilled artist could make a great looking models and textures for a fraction of the file size and complexity the average Blender zoom zoom would provide.
However, the true magic of game optimization happens in code and shaders. Minimizing the draw calls, reducing AI or physics refresh rate / syncing / whatev from each frame or tick to just every third or less, pre-baking stuff that has no interactive elements and isn't seen up close...
this sort of stuff used to be commonly taught in High Schools.