The nice thing about guaranteed money is that it is guaranteed.
Why participate in a bunch of events where there is no guarantee of a payday, instead of doing a smaller number where there is a guaranteed (large) payday?
Seems to me this is why it's different than USFL vs NFL: The Saudis are offering something PGA events do not, a guaranteed big lump sum of cash.
It very well may be aging guys cashing in off their names, but NIL now has college guys who have done relatively nothing cashing in off their names so at least this is anti-ageist.
Personally, I'm surprised Tiger didn't go for it. High nine figures would almost double his net worth according to Forbes. His declining health should have made one last huge payday very tempting. Maybe he thinks the new league would be counter to his current business investments? Or maybe he's afraid the ex-wife would get half?