“Yeah, because AWS hasn’t figured out how to ensure uptime in case some individual server / data center goes down.”
As a matter of fact, whenever there’s a power outage in the US state of Virginia, a large portion of sites hosted on Amazon’s cloud go down. US-East is their largest region, and the place where most sites are hosted.
“If Domain Fronting works, it’s enough. If it doesn’t, you’re out of luck because the international community isn’t going to care about oppressive nations blocking all Matrix servers.”
I don’t know how many Matrix homeservers there are, but I’m pretty sure they’re just HTTP, meaning that oppressive nations aren’t likely to try to block _all_ Matrix servers unless they’re shutting down their nation’s Internet connections anyway. Even if they weren’t using HTTP, a nation wouldn’t likely bother to block thousands of individually-hosted servers unless they were going to completely shut down the Internet.
On the other hand, if domain fronting is all that Signal’s got, all it takes is a big enough player deciding to block those fronting hosts, and they’ll cave.