2018 seems a bit early. 2019 sounds fine if not 2020. I think Sony would be smart to follow Microsoft's lead on this one and get rid of generational releases. For Microsoft it no longer really matters when a new console comes out because the whole game and all library will transfer over with all previous features. Sony releasing a ps5 right now or next year with all new releases will cut off a lot of gamers, especially with how games are more of a service nowadays than a consumer good. Splitting populations and making everyone rebuy games in never fun.