Ummm... there's a lot of meat for discussion here. I'll get the ball rolling:
1. Bikes are lighter than cars. Apples to oranges. Bikes can endo, cars can't. Bigger front brake? Go nuts!
2. Same brake front+rear means same installation tools, same pads, same lever ergonomics, same adjustment skillset, and half price for keeping spares on hand. Keep it simple.
Not to say there aren't reasons to get mismatched brake styles (mostly related to inclement weather riding), but any well-adjusted set of brakes can stop a bike at the speeds one usually finds oneself riding.