"Developers use what the hardware allows."
Nonsense. Developers use hardware as well as they understand within given project constraints.
Optimizing modern game engine to run fast is generally considered a non-trivial task. The more arbitrary the hardware platform, the harder it is to optimize.
Yes, if PC port had to target only a specific, known, hardware and software combination (say a specifiv i7 with gtx 1080) then they could probably optimize the shit out of it.
A console is a fixed, known target. Thus it takes much less resources to optimize for it - thus developers can reuse their understanding from project to project.
The AAA game scene is full of recent examples with crawling PC ports, such as Arkham Knight.