The Spurs' will likely finish somewhere between the 7th and 9th worst record in the league.
A full-on tank might get them up (down?) to the 7th worst record.
A play-in berth would get them the 9th worst record (assuming they don't win two road games in row against higher seeded teams).
If they try to tank but don't get to 7 or try to win and don't get to 9, they'll be at 8 (possibly the most likely outcome).
The chances of getting a top 4 pick are as follows:
7th worst record -- 31.9%
8th worst record -- 26.2%
9th worst record -- 20.2%
That's about a 10% difference between going all out to win and trying to lose every game. A one in ten difference is, at most, what all this fuss is about.
The more likely difference is between 8 and 9, so a mere 5% difference is more realistically what all this fuss is about.
Tanking or not tanking is not a binary thing, although as humans we're programmed to think that way. Rather this situation is incremental, statistical. And you don't get points for trying (or not trying) or thinking good/bad thoughts, although again as humans we're programmed to think that way. That's why when people are asked whether they want a 50% chance to get something rather than 50% of losing something, when it's exactly the same choice, they react differently. And I think that's why we're so excited about trying to lose games in this case.
If you had a 20% of winning some bet, how much better would you feel if you had a 26% chance of winning? Would it make that much difference?
I hope the Spurs to go out and play hard and try to get better as a young team. The "fates" may reward you more for that.