It's personnel. Jazz played switching defense at times and it's not like it helped at all.
The scheme that people call that's just funnel to Rudy is ridiculous, the idea isn't ever to let go players unattended. Jazz even have been playing more at the level this year and doing late switches with Rudy so dying on screens aren't as catastrophic.
The problem with the Jazz start when perimeter defenders need to decide when to help, rotate, switch etc. They lack the awareness to make good decisions. They can't string rotations and they don't run.
Just last game, Mitchell pointed Gay to rotate and missed his own guy for a cut. Too many examples like that over the season. Just poor decisions all around. This game may have been about effort but good decisions save you some of that effort.
Now you may think Quin who had great defensive teams can't make this team buy in because his voice got tiring, it's okay. It may be the case but this team has repeated trust in Quin and talked about what they lack. It's either platitudes or they are incapable of fixing this themselves.