So next year's cap shouldn't be an issue. Worrying about that's a non-starter. That doesn't make his contract good. But it's tenable so long as the team stays under the tax. It was a real move to try to sign an offer sheet that would make SA be a tax team. It seems like both sides would've been served well by doing a sign-and-trade.
I don't think this deal really pushes LMA out the door. As I said before, the Spurs paid Splitter this same APY in a lower cap to be Tim's backup. Like with Tiago and Pau, I'm sure the Spurs are willing to play Jakob any minute with Aldridge that they can. But they are going into this deal content that he won't start.
There's nothing wrong with signing Poeltl in general. It doesn't hurt the team's direction, and not picking a side or whatever doesn't matter. The Spurs seem willing to let their vets expire, not so they can have some maximized amount of cap space but so they can have options for how they want to build around their young players. Maybe that means bringing in bad contracts for assets. Maybe it means trying to lure high-dollar free agents. Maybe it means re-upping the vets and trying again. We don't know, and it won't be something the Spurs will decide until after they get into the year and can see what they have.
And no, OKC is way, way off the rails at this point. They've basically made no trade of consequence, potentially even including the George and Westbrook trades. Presti needs blue-chippers, not a scatter shot. Every GM can tear a team down if they're ruthless enough. Even a -tier one like Hinkie did it. But navigating those assets and turning them into just a few legit foundation pieces is what separates good GMs from mediocre ones (bad ones will just draft a bunch of busts). That Presti failed to do that in this past draft can be defended as him not liking the players. But if next draft comes along and he hasn't traded half those picks to move up, OKC's whole rebuilding plan is going into the ter.