Maybe I'm misremembering, but I thought they used Syncthing as part of a business not directly related to Möbius - as a vendor supplying data management solutions to other companies. I suspect Möbius came out of need for their clients.
I can picture the vendor website in my head, just wish I could remember who it was for sure.
I would eagerly pay for syncthing, it's that important to me. I keep hundreds of gigs moving around using it. It's on my annual donate list already, but clearly that's insufficient.
Maybe the Syncthing-Fork dev will keep it going.
iOS is already more restricted on app sandboxes, and Möbius can handle it in the paid version.
On Android, Resilio somehow has more file access than Syncthing, even without root (it can read/write to either SD card root, while Syncthing can only write to a subfolder of SD0, and can't write anywhere of an external SD). So there's something going on.
That takes a lot more effort.
With Syncthing, I don't have to setup a server, poke holes in my firewall/expose ports, etc.
Plus Foldersync is way harder on battery, I've experimented a lot.
And I've used Foldersync since at least 2010 - it's great, really has it's uses.