Why hasn't adam sandler hosted saturday night live?

why hasn't adam sandler hosted snl since he left? countless others have such as will ferrell, mike meyers, and so on. don't get me wrong i hate sandler now. he puts like 5 minutes effort into writing a movie, makes 25 mil off it, and won't even host snl. he's hosted late night with david letterman. perhaps he's owned by viacom instead of universal? still even neil patrick harris hosted didn't he and he's on a cbs show.