They'll just accept that Xbox One is their fastest selling console and try to keep that momentum introducing a more powerful model, just as Phil teased at Xbox Spring Showcase. Microsoft has been very clear they view Xbox as a platform, not defined by hardware or the specs of a singular console. So yes, Xbox games would be scalable across different Xbox SKU's as a game would be scalable on PC regardless of hardware configuration.
Whether voices on the internet agree or not, if 2 competitors are refreshing their hardware, it becomes a necessity to keep your platform relevant and in the hype conversation.
These things start to germinate very early, and there is a roadmap in place...so no, its not something Sony or MS just pulled out of their rears this year. Working with AMD they knew what the manufacturing nodes meant for transistor count and cost, and that launching at 28nm meant they couldn't pack too much power initially for a high perf green device. They also were not oblivious that launching 1080p/30 machines was not innovative in a market shipping 4K display panels. They simply played the cards they were dealt with to launch in 2013.
I'm expecting the new consoles to use 20nm, as 16nm is pipedream to cram the custom architecture they use. AMD/Nvidia will be at 16m this year on the GPU alone, and the consoles need 8core APU's with the custom memory configuration and gates that were architectured for them.
PC I i7 3770K @4.5Ghz I 16GB 2400Mhz I GTX 980Ti FTW
Consoles I PS4 Pro I Xbox One S 2TB I Wii U I Xbox 360 S