That already exists as their cloud virtual desktop service.
Edit: I could see them releasing a line of products and an ISO for Windows365Client that just makes the machine a thin client dedicated to rdping, or I guess Windows Apping now, to the Windows365 PC.
The only thing I'll tack onto this is that with the introduction of Signal usernames, you still have to give Signal your number to verify that at least on some level, you probably are a real person. As someone with 5 different phone numbers, probably doesn't stop spam as much as they'd hoped, but more than they feared, but at least now you don't have to give that Craigslist guy who uses Signal your phone number, just your username. Is that the best method? I dunno, but but it is something.
The thing keeping me from self hosted email is despite working in the tech field for 8 years, I still can't seem to wrap my head around SSL certs, especially trying to use one from Let's Encrypt. I don't know why.
I think it's Darren Kitchen that always says involuntary offsite backups. Also unpatched layer 8 exploits.