Furthermore, I expect NX to be an iterative game platform, with hardware updates pushed out every 2 years or even quicker, just like we can expect to see with the PS4 and Xbox from now on.
Please god, no.
It's the future Soren! We all manage it with our phones and PCs and they are more expensive devices. You won't be forced to upgrade, it'll be up to devs to decide to support older models and they will often strive to do so. But there will be a gradual march forward in processing power and us gamers will migrate forward at our own pace.
The only reason I upgrade my phone is because I get it for free when i renew my contract. All my laptops and PCs have lasted me 4-6 years and my current Mac Mini/Mac Book Pro combo are on age 3 and 2 respectively, with no plans to replace them soon. I'm not going to buy a Scorpio, Neo or any future NX upgrade because that **** is too much. I don't have the income to upgrade all my machines every 2 years nor do I trust developers to support legacy versions far along anyway.
It's the same as companies trying to capitalize off cord cutters. A while back we only had to worry about Netflix and Hulu. Now there are far more people in the game and eventually, some just don't get supported.