I agree, and by no means is it a replacement, but https://syncthing.net is pretty damn interesting if you want to control your own data. https://www.syncany.org [now abandonded] was a cool twist on the idea using cloud storage in a secure way.
Though every time they release a new major version it breaks compatibility with the older major versions and this happens quite often. They need to stop doing that if they want mainstream adoption.
There seems to be one open source project that aims to implement Resilio Sync's model: