Sounds like from a technological point of view Solaris had nothing to keep such customers. Maybe paying a shitload of money for a system that is dog slow didn't seem like such a great idea.
Supercomputers care about three things:
in no special order.
Solaris was once big in that business. A long, long time ago. Today? Noneexistant. Must be Solaris performance, scalability and robustness that made those people flock to it.
For almost 20years.
Sleeping well on all that SunOS tapes?
But according to you, Solaris must suck because it only runs on SPARC really well. A very... specialised CPU.