Q – Why do consoles massively outperform their PC equivalent hardware?
A – Because they use a streamlined software stack and optimised hardware.
Let’s ignore the former for it doesn’t tell us anything interesting, for while every real console (i.e. not ouyu), will seek optimised software and hardware only the latter will help us with the big questions. Consoles are machines specifically designed to pump out graphics so the determining factor will be the GPU, and from a console vendors perspective what is the prime consideration when choosing a GPU?
Price/performance. A combination of the number of transistors and their clock speed.