There is no next generation thing for Xbox even it delayed to 2019, not because powerful or not, it's because that doesn't match MS's currently strategy.
Microsoft from here on out will release major console upgrades/refreshes every 4-5 years to ensure they have a product with Microsoft and Xbox branding capable of playing some of the latest games at, or close to, their best. They'll use it to drive support and engagement of their digital storefront for games. So Microsoft will always have a more powerful system.
However, it isn't entirely true that Microsoft won't have generations. I don't think people realize yet what Microsoft is really doing. My suspicion, and I suspect I'm right, is that Microsoft are guaranteeing,
for now, that Xbox One gamers won't be left behind and all games are going to be shared between Xbox One/S and Scorpio. However, I feel the bigger promise being made, and the one they really feel is the more important promise to keep, is that gamers will no longer need to start over when they buy a new system. All of the games they bought and enjoyed for previous consoles, starting with Xbox One, will be compatible and fully playable on all Xbox consoles going forward. Xbox One will get a solid 3 to 4 more years where everything that releases (with the exception of some Scorpio VR titles) has an Xbox One version. However, once Microsoft is coming around to their Scorpio successor, no way will that continue to be true.
The new "you won't be left behind" promise is going to be made and kept for the next 3-4 years for Scorpio. Scorpio will be the new baseline for game development once a more powerful xbox releases because It simply wouldn't be practical to try and stretch releases across 3 classes of consoles where the gap is so large from Xbox One all the way up to the Scorpio successor. By then, if people want to continue taking advantage of new releases they can opt to upgrade to the obviously now much cheaper scorpio, or they can choose to upgrade to the more expensive scorpio successor. Xbox One gamers who didn't upgrade before will now find it in their best interest to finally pick an upgrade if they want to continue playing new titles on Xbox. I don't rule out devs being able to create games for Xbox One still, but should they choose to do so, they run the risk of really holding back the version for the scorpio successor unless they do some extra work.
But as I said, I don't see Microsoft minding too much setting Scorpio as the new baseline for development after a certain number of years have passed. It'll be much cheaper for people to upgrade to by then anyway. That's Microsoft's strategy going forward, I'm certain of it.
