The story as I understand it is that Sun wanted to license Solaris on a number of hosts basis while Google considered the number of servers they had to be a critical secret.

> maybe we’d all be running containers based on solaris zones

There were a lot of nice things about Solaris. The Solaris engineering org was amazing, full of visionary giants. ZFS, Zones, DTrace, mdb, SMF (systemd, but done better and ten years earlier), the fault tolerance stuff -- all created by engineers as skunkworks.