The article you linked to doesn't say Solaris is gone either. It mentions large numbers of layoffs, but acknowledges that there is still a Solaris dev team in place (even if a significantly smaller one).
(Disclosure: Former Oracle employee, although I never worked on Solaris.)
Some were ported to Intel. Others (HP/UX) became dedicated big iron operating systems. HP/UX and Solaris are still being updated and used.