Ubuntu will still be very compatible with Debian, which provides second-only-to-Redhat levels of compatibility and package availability. The problem is their internal application ecosystem; instead of contributing Wayland and GNOME/KDE, they decided to reinvent the wheel. Yes, they have Samsung and other corporations on-board to support their vision, but it doesn't contribute to Linux/GNU overall.
I dumped Ubuntu when the Unity Netbook Edition switched from the (beautiful) EFL libraries to Qt, which added significant performance penalties, and then the main distro adopted the new interface. It felt like everything could've been built upon Plasma 5, but because it wasn't controlled by them, they had to make their own in order to be XKCD-927 Compliant.
I dumped Ubuntu when the Unity Netbook Edition switched from the (beautiful) EFL libraries to Qt, which added significant performance penalties, and then the main distro adopted the new interface. It felt like everything could've been built upon Plasma 5, but because it wasn't controlled by them, they had to make their own in order to be XKCD-927 Compliant.