Advertising is very expensive and political candidates have to pay retail rates. As the old adage goes, half of it is wasted but you don't know which half. However with political ads, all of the money spent on the losing candidate is wasted in a certain sense.

As media has fragmented, you really have to spend a lot to get in front of enough high propensity voters, and even more to turn out low propensity voters unless you're organically good at getting invited on to podcasts.

IMHO, this is the problem with trying to regulate elections in the US. Elections have always been intended to be controlled by the wealthy. This is nothing new. So, in the unlikely event that Congress does add regulations that neuter Super-PACs, and the less-likely event that the Courts uphold the regulations, well, they'll just come up with a new way to fund the desired outcome. They'll call it Super-Duper-PACs or Turbo-PACs or some shit like that.

That's across all elections and issues, not just the presidential campaigns. About 30% of the top ten conservative PACs listed are for single senators or DeSantis. Lumpin them all together as Pro-Trump is just as dishonest as ignoring PACs.