It's not a matter of "flipping the switch", though..this isn't last year's Spurs that flipped the switch after struggling to beat good teams, all year..
The Spurs aren't playing poorly, overall..they've already defeated the Warriors, Grizzlies, Clippers, Cavs, Mavs, etc..
Their disappointing losses have been against mediocre and bad teams, which is a clear indication of coasting and complacency..of course it's frustrating for the fans, since they are wasting games in a conference where Memphis and Golden State are trying to win the regular season championships, but it doesn't mean much in the long run..
Whether the stupid losses to bad teams are going to kill them later on is debatable, but I think it's very evident that Pop doesn't care about this year's regular season, based on his tendencies, so far..this team has had way too many injuries(exacerbating the age concerns) to give a about getting a top 4 seed IMO..