Comparing hardware itself is perfectly valid. Console APUs are not far removed from regular desktop / laptop APUs. Console makers try to tweak them to stand out, but it only goes that far. AMD has no reason not to offer comparable or even better in performance parts to laptop and embedded system makers. Unlike incumbent consoles, the later aren't limited with artificial requirement to make one model with fixed hardware in almost a decade. So there can be a whole range of APUs out there, some even better than what console makers are going to be using (especially as time goes on and next generations are coming out, while consoles are lingering on their selected level).
And combination of desktop CPU and desktop GPU will always have higher raw computational power. What APU usually is good at is may be faster CPU to GPU data transfer, due to full integration. Something like HBM memory can also give it a boost.
In regards to what games do to utilize hardware - that's completely up to developers, engines and etc. But we can make an assumption that modern games are already written with maximizing parallelism of both CPU and GPU, and therefore scale according to hardware resources provided. Given that assumption, incumbent consoles don't look like anything impressive in comparison with desktop systems.