I could see Sony releasing a new portable system but it doesn't have to follow the Switch example completely. It could be a tablet that mainly streams from a ps4 and could be used with a VR visor to run playstation VR games but has portable functionality too. It's tech could be sub ps4, maybe 4 fast cpu cores to match 8 jaguar core performance and graphics hardware to reach no more than 800 gflops docked and perhaps a third of that in portable mode. This would allow long battery life, 4-5 hours plus. PS4 games could be easily recompiled/adapted to work with it with resolution and detail dropping compared to a standard ps4. It would perform easily above Switch.
Clearly Switch has shown the hybrid format can work and to be honest I can't see this not being copied by other console manufacturers. They may claim otherwise up until they announce their own versions of hybrid consoles. 3 years from now we will probably have a glut of Switch type systems, sony, microsoft, steam, android, ios are all possibilities.