Gregg Popovich is obviously the premier coach in the NBA today. If he were our coach, we may have a few more wins, but it would be pretty irrelevant as we are missing our best player.
Every coach eventually becomes the enemy. If Popovich sticks around after Duncan, Manu, and Parker are gone, I am sure fans will be calling for his head, too. If Jerry Sloan can get lambasted and thrown out to pasture, anybody can.
As a side note, I am fine with Doc as our coach for as long as he wants to be. We have been lucky to field such a competitive group for these past 6 years. While there are a couple of other coaches out there that I wouldn't mind having, I am of the mindset that the grass is always greener.