Ubuntu support: I feel ready to bet a case of beer, that that won't happen.
oVirt lives in a niche, which doesn't have a lot of growth left.
It's really designed to run VMs on premise, but once you're fully VM and
containers, cloud seems even more attractive and then why bother with oVirt (which has a
steep learning curve)?
Of course, you can run oVirt on some clouds to get a bit of your own abstraction and
mangement layer, but cost vs. benefit are doubtful, especially when you can change the
code that gave you your infrastructure as code.
I still see some potential where you need a fault tolerant redundant physical HCI edge
built from small devices like industrial NUCs or Atoms (remote SMB, factories, ships,
railroads, military/expedition, space stations). But for that the quality of the software
would have to improve in spades.
If oVirt in HCI was as reliable as CentOS7 on physical hardware, pure software update
support could perhaps be made to cost no more than the hardware and you'd have
something really interesting.
But that would require large masses (millions) of deployment to make worthwhile, which
can't happen with somebody doing a huge amount of initial subsidies. And who would be
able (and motivated) to shoulder that?
But that's really just my personal opinion, Didi is the much better authority.