You are comparing a multi millions ( if not billion ) studio with teams of 1-5 people
))
Yes, you can achieve high quality graphics with low/ decent hardware requirements. But, you need to spend loads of time to optimise everything ( code, meshes, materials, etc ) and you need people with the knowhow to do it.
Unreal/ Unity provide a good balance between hardware requirements and quality by default, and that is what most game dev's are doing, just keep the default's. If I had 1 million $, I could deliver a AAA ( or at least AA ) project, but most dev's here don;t have that kind of money
, and I am pretty sure PoolSide doesn't have that kind of money either