Well Sony/MS can't really put in CPU cores that doesn't exist at the time. And I believe Mark Cerny talked about the CPU performance of PS5 once. He said he offered more CPU cores to devs but it would come at the cost of GPU. All the devs immediately said no, realizing GPU performance had to be prioritized. And the proof is in the pudding. You see how resolution targets are gradually lowered as this gen goes on. We went from 1440p baseline to 1080p and now some games even go below that. This is the biggest sign that developers are hitting GPU bottleneck first.
So with that in mind, current-gen consoles have been designed properly, prioritizing, at the time, cutting-edge GPU over cutting-edge CPU. Sony did the mistake of the latter with the PS3 and are not so keen on repeating it.