That's probably why these older OSes are still available for tech support at any Apple storeNope. Tiger, Leopard, and Snow Leopard are all marked as unsupported under the support status. They are dead to Apple. XP has outlived them all.
Lion and Mountain Lion still get minor security updates, but will no doubt be ditched as soon as a Mavericks successor is released. Apple drop full support off an OS almost as soon as they release it's successor.
Serious sysadmins still rely on SL Server since Lion dumbed everything down and Mavericks still haven't recovered from that fall.