You're conflating two things.
1. "whatever amount people would like to believe is going to be spent" shows a skepticism that money won't be spent either in part or in whole. Insiders have told us that in some cases they know of, in which it seems money was cut, the fact is that the money was spent in full, only that some of the things had cost overruns leaving not enough money to do all the things they had hoped to do. All the money was spent, but we got less than than we hoped for from it. Which leads to your second point...
2. "...is going to be spent wisely" goes to your point that there are indeed cost overruns. Was the scope of the build too big? Were the estimates the result of gross incompetence? Was the supervision of the construction grossly incompetent? I certainly don't know what the cause of the systemic cost overruns are. But I acknowledge they exist.
So, when people moan that they doubt the full $60B will be spent -- despite showing up in a plenitude of SEC filings and mentioned by many execs over and over doubling down on it really happening -- by implying that Disney will secretly not spend that much... that's just uncalled for. It's point-scoring against Disney for whatever reason they have for point-scoring. Billions have been spent over the past decade, and so that kind of skepticism rings hollow. Very, very, very hollow.
However, if they want to make the point that the $60B isn't going to buy us all the stuff they say (which, by the way, is very little so far... we have a bunch of insiders relaying a lot of wishes and hopes, but that's not official Disney); then that is indeed borne out by history of cost overruns. Which is a worthy critique to lob at Disney.