I see the sense in that. We're seeing amazing games still and PS4 is still selling. There'll be significant tech advances - new architecture from AMD, raytracing/data-traversal processors, SSDs - that'll make for a machine very different to what's possible in 2019/2020.
This does conflict with the Navi reports though. Navi is supposed to be superseded by a ground-up new architecture in 2020/2021, which you'd expect a 2021 console to target. Why would Sony be investing in Navi to release later this year if its not going to drive their next console? So either Sony aren't investing in Navi and that rumour is bogus, or that relationship is for something else, or we're still looking at a nearer release.
This does conflict with the Navi reports though. Navi is supposed to be superseded by a ground-up new architecture in 2020/2021, which you'd expect a 2021 console to target. Why would Sony be investing in Navi to release later this year if its not going to drive their next console? So either Sony aren't investing in Navi and that rumour is bogus, or that relationship is for something else, or we're still looking at a nearer release.