The PlayStation 4 could inevitably become unusable in a few years, unless you fancy cracking it open and tinkering with it. Apparently, the console requires a working CMOS battery to play games, regardless of whether you purchased them physically or digitally. Replacing the battery is only possible for as long as the PlayStation Network supports the PS4, too.
https://www.notebookcheck.net/A-dead-CMOS-battery-could-cripple-the-Sony-PlayStation-4-in-a-few-years.529381.0.html