Saunders out in Detroit

This is what I don’t get about the NBA. Flip Saunders, despite another trip to the Conference finals and a generally good coaching track record (as opposed to someone like Doc Rivers who is perpetually over coaching a good team) has been fired by the Detroit Pistons. This is the kind of willy-nilly coaching changes that just make such things in basketball really absurd. What’s the average life span of an NBA head coach now, 3 years? Maybe?