Sounds like you're diagnosing a disease before knowing whether or not anything is wrong in terms of how often a team is down 10+ points and their winning percentage in such games.
Sounds like a good research project, tbh. I think Spurs are probably somewhere in the normal range but I could be wrong.
Different question, tbh. I agree that the number of blowout losses the Spurs have suffered this season is out of the norm for teams with similar records. But they've probably blown other teams out more often than teams with similar records ... so, I don't know what there is to take from either number. Could be as simple as the Spurs get blown out when their porous defense is figured out and they can blow out other teams when their defense plays better than usual. Maybe something more sinister is afoot but Occam's razor would say otherwise.
Completely different question, tbh. Do I think differently about this team going forward because of the type of losses they are suffering? Not really. If they were blowing close games left and right but their record and point differential were the same, I wouldn't be more optimistic or less optimistic, tbh.