If PS has any chance of creating a portable/hybrid that plays console games, their best chance is explained in this article.
It talks about AMD's x86 Zen and ARM K12 processors being developed together with high compatibility. It also mentions a potential K12 APU, with two cores and a 'next gen' GCN arch (Vega?). The biggest thing is that this APU is supposed to be around 02w TDP, which is insanely low. If this is true it may not be all that impossible for PS to do it from a hardware standpoint. If the compatibility is there, then software shouldn't be too much of an issue either. I've been waiting to hear more about K12 after AMD went dark with it right around the time that Ryzen launched. Most recent articles I can find say K12 was supposed to launch sometime in 2017, but AMD seems to be keeping quiet.
If PS could create a PS5 portable/hybrid using K12 and have PS5 using Ryzen, with both using future Radeon GPU tech, it could work. Not to mention if they could achieve PS4 BC for all PS5 hardware.