all of FS2020 will be running on Azure in the MS Cloud, and you basically only install a local interactive video player.
Not quite. Apparently it will be a "three-layered" approach:
¤ online, scenery streamed,
full quality;
¤ "pre-cached": download scenery in advance, then use cache during actual session;
quality?
(in theory ought to be the same as above, but will people (be able to) pre-download
and store 10 GB for their local 30nm GA hop?

) ;
¤ offline, nothing cached;
reduced quality (how much?)
In any case, I'm sure purchase of new more powerful hardware will still be required. Old habits die hard, and Tradition must be honoured...
Disclaimer: AFAIK.
Cheers,
Martin