The 950/950 XL were made for the "Fans" as this has been stated many times. I can tell you that MS will improve continuum features for these phones and other things, but the real focus will be on their spring lineup of phones that are supposed to be their big push into "mobile". And I do put quotes on it because it does not necessarily mean a plain phone, it could be a more advanced 2-in-1 with superior continuum. And of course everything before it will just be there and can get the apps. Likely a lot of phones won't be able to take advantage of many new features.
So for the fans is sort of like saying "here's something to hold you over while we make the real stuff". And that's just what they did. Why do you think they don't care that 50% of the devices won't get windows 10? They will only care about their future spring line up. And any phones with continuum. the 950/950xl is also being used by them to collect data on continuum to make the OS better. They know that fans are more likely to join the insider program. It also gives them some relevance in the mobile segment. But as the shares dwindle their expectation is to create new categories like with the surface line.
I sort of regret buying the 950xl. The push for features for continuum is way too slow. Summer is a long time to wait to get a few features. And I think build does need to push continuum. It's an interesting features, and if that's where their future is going it should be mentioned. A lot of apps can be deployed for mobile/desktop but they won't support continuum by default. So while I have a lot more apps in continuum, i'm still forced to RDP as not all my apps are available nor do I have good alternatives.