Well, if anything should teach the Spurs the lesson about "staying put" is the fact that anything and everything can happen in the offseason or during the season that can dramatically change the postseason scene.
On the one end, We saw 2 major le contenders at the start of the season, mortgage everything they had and fall far short of their expectations in Dallas and Pheonix.
On the other hand, We saw 2 non-contenders last year and teams who haven't made it out of the first round in 3-4 years, make it all the way to the NBA Finals this season because of major trades and aquisitions.
Pop is partially right in that, sure, the Spurs obviously did have a good enough team this past year if they managed to get past the Suns, win a Game 7 against the Hornets on the road, etc. But he hopefully he also realizes just how quickly things can change in the league and that matching up with the younger, athletic teams in the West is going to be a great challenge.