The subscription based model makes sense as there are petabytes of data if I have read correctly. It will require an internet connection capable of streaming the data, as well as reading data from the PC regarding position, speed, etc...
The good news is a lot of the computation of the objects, AI, and scenery will be done in the Azure cloud, so a lower-end PC (or XBox) with a strong internet connection may have good fps. If I'm right here, Microsoft solved 2 nagging issues with simulation: the need for cutting edge, over-clocked computers, and the need for massive storage.
The downside here would be terrain developers ( landclass, vector, photoreal) are out of work. This is all streaming photoreal, all coming from Microsoft. And we'll be paying $5-$12 a month, every month, for years, for the subscription. People on fixed incomes will have to tighten their belts a bit. PC replacement purchases should be cheaper, internet costs may be higher. We'll see if payware DLC is controlled by Microsoft, and how much we'll get with the base (included) aircraft.
I think modelers will still have a market. New or replacement airport buildings, landmarks, aircraft. Mission builders will definitely have a job to do.