Correct me if I am wrong, but Sony is just choosing to take advantage of the smaller nanoscale manufacturing process now available to AMD, yes?
Perhaps Sony and others are just using the opportunity available to them at this point in time, one that still allows them to not break compatibility of software with older hardware.
It may in fact take another five years before there's a real cost benefit to increasing performance while remaining arbitrarily confined to a limited thermal output, all while willing to break software compatibility, no?
Because so far I think that's been one of the hallmarks of what defines a new console generation, which is the willingness to break software compatibility.