Utah didn't have to pay the supermax, they have their rim protector that fits their defensive scheme beautifully for the next several years, and they have their stars signed through 24/25. Utah doesn't attract elite outside talent, so if you have homegrown guys, you simply *have* to pay a premium for them.

They only really had two choices:
1. Sign Mitchell and Gobert, hope things go very well in a coming season-- maybe a couple contenders get injured, maybe Mitchell takes a leap, maybe a rookie is better than they thought, etc.-- and, if that happens, maybe they can convince a third star to come through, or maybe they can just totally luck out into a Finals run in the next four years.
2. Tank, because without Gobert, you don't have the personnel for this year (or realistically next year), and you're just hoping the right pieces come to you in the draft or in a trade. You also probably have to look into dealing Mitchell, because he's not going to be happy stuck on a shitty team for five years. So it's just a total restart.

And really, that's not much of a choice-- especially with the flattened out lottery odds. They simply would never be bad enough to be top 3 in the odds/get at worst a top 6 pick, so they'd just linger around late lotto in perpetuity. A miserable existence. Whereas with Mitchell and Gobert, they can be somewhere between a 4 and 6 seed annually, safely a playoff team, and it's not impossible things could fall your way for a WCF run one season. Weirder things have happened. Like, between now and 2025, if two of AD, Kawhi, Luka, and Jokic get hurt in a given year, the door is open for a team like Utah to sneak in and make a deep run.

Meanwhile, Gobert gets his last big contract-- the biggest for a big man ever!!-- at a time when his type of big-man play will grow increasingly out of style in the coming years. He needed a big deal, he worked very hard the last few years to get it, and he got it. Great deal for everyone involved.