Dtrace, zfs and smf were nice but came too late but they are things that appeal the engineer, not the manager that sign the contracts. And Sun was already on life support when Oracle bought them.
Sure there was still a lot of companies still using mostly solaris back then - I worked for 2 of them as a Solaris "expert" somewhere during last decade - but all of them already had projects running about replacing Solaris for more cost effective redhat, even those that bought exadata racks.
"expert" meaning I was still one of those survivors still young enough to be still willing to work in an operation team and having more than 5 years of experience administrating Solaris and AIX shit.
I must say I loved the integration of zfs with gnome2's nautilus back then on opensolaris. I used it for a while as my daily driver at home.