Primo over Sengun is inexcusable. But pretty much the entire NBA passed on Sengun. Even SpursTalk's dreamboat Presti passed on him -- nope, he drafted him to benefit the Houston Rockets. Oops.
Branham and Wesley were whiffs, but it is not hard to think they could make it somewhere else, just not on the Spurs.
You're entirely wrong about Sochan, who is one of the top five players in his draft. Vassell is good, even if he's not going to be the volume scorer we want.
And you fail to see a pick-up like Julian Champagnie.
Where these sorts of analyses go wrong:
1. No team gets them all right. Even dreamboat Sam Presti has ed up A TON. You just forget about them because you want to forget about them and are secretly Thunder fans.
2. Look at who was available at those picks. Really look. I mean, honestly, look. When Primo was picked, the obvious alternative was Sengun. The other was Trey Murphy, whose advanced metrics were pretty poor tbh and he didn't play a position of need. Otherwise there was no one consensus in that range who was left. It was a very weak draft at that point. For the Branham/Wesley draft, the draft was also pretty much over at that point, other than some stragglers.
3. You always mess up thinking things like Primo was never going to be good. We don't know. He had flashes (wrong way to put it). Players develop in different ways.
To me, the Spurs drafted and developed late picks like Kyle Anderson, Derrick White, Dejounte Murray, drafted Tre Jones, got Sochan completely right, did well with Vassell, got Stephon Castle completely right, and picked up Julian Champagnie and to a lesser extent Charles Bassey. They screwed up with Primo and tried out guards in Branham and Wesley in a draft that was very thin at that point.
That's it. They still need a few pieces but they're still rebuilding and the draft history is nowhere near as bad as you think. I know you get your jollies off OKC, but again they're only where they are because Kawhi Leonard forced LAC to trade them Shai and a big wad of picks and they got lucky that they sucked bad enough to get Chet.