That's an interesting question. I suspect the answer will be tied to the success or at least potential this initial 'test' demonstrates.
Let's assume it is successful. The move to x64 and GPU processor families that are closely tied to PC GPU's offers some interesting possibilities. What I could foresee is something similar to how PC and phone games work. It's a sliding scale of compatibility through time.
The nature of the architecture means reverse compatibility is possible for as long as the architectures are evolutionary, and the OS / API's do not change dramatically. Eventually you may reach a point where it's no longer worth it to keep the baggage around, but usually that's over many generations ... and by then the hardware delta is sufficiently powerful that emulation may be possible.
The bigger question here would be forward compatibility. Let's assume that we see something like a 3 year span between hardware releases continuing. As long as they keep forward comparability for one generation (ie. PS4K and PS4 ... then PS5 and PS4K ... etc), you're guaranteed games for 6 years on any given console.
So fundamentally a console would last as long as at always has, but with the ability of a user to get better graphics along the way. And unlike with phones and PC's, developers will only ever be targeting two locked hardware skus for a given title build ... unlike the myriad configurations the former necessitates.