I don't see the big deal, tbh. You're comfortable spending $10 million in cap space to fortify the backup center position for a non-contending team? That ....... makes no sense to me.
I think the Spurs should value cap space extremely highly. They obviously aren't going to trade their way out of their current position so having a massive amount of cap space in 2021 should be the focus. Throw part of that away to lock up Poeltl for twice the going rate of a run of the mill center? Yeah, no, I'll pass on that.
I'd spend cap space to retain Derrick White. He's a valuable piece to any type of team. But Poeltl, a guy whose ceiling is a low end starter? I don't see how that's justifiable. Give me $10 million more in cap room than a guy whose archetype is nearing extinction any day of the week, tbh.