It's more than that. Ryan Hall was a ranked fighter and doesn't possess any extraordinary athleticism. Plenty of guys throughout the sport are just serviceable athletes. A few of them even subpar.

Collegiate / competitive high school wrestling is the difference maker in my opinion.

There is something you learn about yourself when you routinely physically compete with another person roughly your equal and you are both giving 110% resistance. Fighting with everything you've got. You get that all the time in wrestling.

Sparring is great at weeding out people who simply have no business in the sport, but it won't weed out the people who can't compete at a high level. There are plenty of people who are beasts in the gym but fall apart on even the regional level. There is a mental aspect to fighting that you only encounter when you face another man fighting back at 100%.

Punk got hosed.

The purse money is the appetizer for McGregor and any other champion. The PPV points are the main course.

Punk brought in tens of millions of additional revenue.

It's very easy to argue that stars like Ronda, GSP, Conor were the most underpaid athletes of their eras, but I'd argue unironically that it was probably CM Punk.

https://www.forbes.com/sites/mattconnolly/2016/09/13/reports-cm-punk-more-than-doubled-ufc-203s-pay-per-view-revenue-drawing-power-among-mma-elite/?sh=32df23376b37

Meltzer, kind of the sports authority on this stuff, estimates that Punk more than doubled the buy rate and resulted in $30,000,000 more generated.

CM got absolutely fucked.

He should have made $5,000,000 to show or got PPV points.

Meltzer estimated he brought the UFC $30,000,000 in additional revenue.

Jake Pauls first fight with was "triller" promotions.

There is zero reason he couldn't have just done it himself from the start, and I'm sure he'd tell you the same in hindsight.

If nothing else, doing it yourself is also used as a leverage when dealing with another promotion potentially working with you.