Why not the vertical integration of Oracle Solaris servers, IBM vertical integration of IBM i, z/OS or z/TPF, Unisys vertical integration of Clearpath MCP or OS 2200?
I think perhaps Solaris had a bit of that under Sun but I can't imagine that being the case under Oracle. And I'm not really an enterprise infra guy so can't really speak to IBM or Unisys offerings.
The others suffered "ecosystem collapse". With Oxide you won't be stuck on a "burning platform", your main risk is that the value prop for the hardware & management experience doesn't play out.
Oxide costumers want to run standard VM that they normally run in public cloud.
Do Oracle Solaris serves come with a horizontal scale out cloud infrastructure? As far as I know they don't.