Basically the "no crap Sherlock" answers, and remarkably similar to things I and others have posted for months about this in the other thread.
As to the issue itself, it is not a hard nut to crack -
* The WDW experience has itself, especially in the past 5+ years, been pruned of virtually every bit of extra or special something that it used to have - accelerated by the pandemic, but it was already happening (and people aren't accepting "pandemic" as an excuse any more for lack of anything)
* Prices have skyrocketed at the same time, giving way less experience for way more money
* They have alienated a lot of those who were addicted to "the magic" who started to realize that going to WDW once or multiple times a year, paying more for less, can spend the same amount of money and go on a real European vacation, or spend two weeks on an all-inclusive resort somewhere, etc.
* The post-pandemic "I gotta get out of the house!" boom is over, and those people aren't eager to come back
* The lack of anything meaningful/new that is of interest. I'm sorry, the MK getting it's first E-ticket in 30 years is...Tron? A ride so short the television commercial for it is longer than the ride??
* The absolutely absurd level of pre-planning, up-charges, logistical nonsense in what used to be (and most consumers expect) to be a care-free experience
The heat is much less-so, IMO - since trips are planned months in advance, and people have sweltered in summers at Disney since they opened (I never have, wouldn't catch me dead there between the end of May and at least September in any year). As well as the "political climate" - I'm sure of the few who actually do let that affect their vacation choices either way, balance out with those who go to "support Disney", but in any case, just isn't what this is about.
This is about the last decade or so of degradation in the value of the WDW experience that has finally come to roost.