Just a guess: Vendors certainly seemed more focussed on getting people to use complicated virtualization schemes with proprietary hypervisors. I wonder if it w

Just a guess: Vendors certainly seemed more focussed on getting people to use complicated virtualization schemes with proprietary hypervisors. I wonder if it was more a matter of man-power at that point. In comparison, Sun was already selling systems so the value of selling virtualization separately so zones may have ended up being an elegant integrated solution. I'm not sure of the FreeBSD jail history but there may be a similar story to tell if you look at the source of the contributions.