There is a lot of blame to go around, so I don't think Pop is solely to blame like everyone wants to make him out to be. He is not responsible for every single decision that the Spurs organization makes.
I hold Pop accountable for leaning on the vets more than he should...especially when it's been made apparent over the last two and a half seasons those parts just don't fit well together. He puts way too much faith in DeMar for extended periods which freezes out the other guys on the team. His reliance on Mills continues to be disturbing despite Patty starting the season well.
That said..tonight is a perfect example that just throwing the young guys out on the floor and letting them play isn't a quick fix. "Learning on the fly" only goes so far.
I hold the FO accountable for stockpiling a bunch of guards and putting all their chips on a small-ball "pace-and-space" style of play when none of those young guys are particularly good shooters. Getting Vassell and Dieng are baby steps in the right direction, but it's still hard to figure out who is going to emerge from the pack of Murray, White, Walker, and Johnson. There is a lot of deadweight that needs to be dropped.
And I still blame ing Kawhi and Uncle Dennis for planting the dynamite. This team was heading in a good direction and being built around Kawhi, and has been picking up the pieces ever since that blew up. The Spurs are known for doing right by their veterans (which is the only compe ive advantage they have left in the free agent market) which led to them coddling Aldridge, Gasol, DeRozan, Mills, etc...and depending upon what happens this summer, it looks like it's going to be another long few years ahead.