Perhaps more importantly, there's essentially zero difference between what they'd do this year one way or another given that they've already committed to Xbox One support for all Scorpio titles initially. They can fully intend to move beyond generational incompatibility this year and change their mind down the road, or follow through.
We won't actually know until the console after Scorpio comes out.
I think we will know a lot sooner. The reveal event (or E3 conference) and the console's branding should tell all.
Plans may always change, but it has been stated time and time again that continous back compat like a pc has is what they are planning. Eventually older hardware will become obsolete, obviously. It is not a lot of assumptions at all, imo, and the only plausible way forward given they stick to their words. Naming scheme is another thing entirely, but they have been very clear about their purpose.
What other possibilities do you suggest?
http://www.neogaf.com/forum/showpost.php?p=233073037&postcount=7548