Microsoft would like to move beyond regular console generations and as such, the era of consoles being released every 5+ years could be over. Speaking with Engadget, Microsoft's Aaron Greenberg explained the company is envisioning a future without "console generations."
Future consoles, like the upcoming Project Scorpio, will be joining a "family of devices." That family is going to be more regularly updated and likely feature inter-system compatibility as much as possible so that the newest console isn't required to play new games (and the reverse.)
It's one ecosystem. Whether you have an Xbox One S or Project Scorpio, we don't want anyone to be left behind. - Greenberg
When Project Scorpio is released next year, it'll be the only Xbox to support virtual reality gaming. VR titles will also be the only kind of content that's exclusive to the system.