Getting back to the "How much money does Professor X have" discussion for a moment.
I just recently reread the first 325 issues of X-Men. From Lee and Kirby right up through Age of Apocalypse. That includes all the crossovers, annuals, minis and everything else. It was a lot, but it was fun.
Anyhoo, in issue 144 there was a scene where Charles asked Warren for financial help. The issue before Kitty was home alone and she got in a big fight with a demon on Christmas Eve. They wrecked a big part of the mansion, the danger room and the blackbird. The discussion with Charles and Warren went like this:
Warren: "Problems, Professor?"
Charles: "I've been totaling the reconstruction costs for the danger room, the hanger, the blackbird aircraft, the mansion itself ... they are considerable."
Warren: "If you need money, sir, all you have to do is ask."
Charles: "I appreciate that, Warren. Thank you."
Besides the Kitty fiasco, the X-Mansion got razed to the ground twice. Once in X-Men 154 by an alien race called the Sidri, and then again in X-Men 243 by Mr. Sinister as part of the Inferno storyline. That's twice the entire school had to rebuilt from the lower levels up. That kinda thing costs $$$$$$.
I did the same thing with Avengers a few years ago, as well. Every issue from number 1 by Lee and Kirby right up through the Jonathan Hickman days. Again, that included all the annuals, minis, crossovers, ect. Two things struck me about that. One, the Avengers have been pretty consistently great. There were a couple of short dry spells but overall it was a fantastic read. Two, the absolutely insane and staggering amount of property damage. No lie. The entire city of Washington D.C. got leveled twice. Once during the Kang Dynasty and then a few years later in the big Fear Itself crossover. The whole city gone. The White House, the Capital Building, the Washington Monument. I mean, I don't know how many times the Avengers would get in a big fight somewhere, whether it was a small town in Alaska or Oregon or wherever, or a large city somewhere, and the place would get destroyed. At the end of the story, someone would walk up to Iron Man and say something to the effect of "What are we going to do? Our homes are gone." Tony would just casually say "No problem. Just contact the Maria Stark foundation. They can help you." Now, as I'm about halfway through the run I'm thinking to myself "Just how fucking much money does the Maria Stark foundation have, anyway?"
The answer to that question came at the end of Avengers Disassembled. Avengers mansion got destroyed (AGAIN) and as they're standing in the rubble, Steve said to Tony "We're going to rebuild, right?" And Tony said "No." Steve said "No?" "There's no more money" Tony said. "The Maria Stark foundation is broke." Well, that didn't exactly shock me. Eventually the mansion did get rebuilt, but it's probably been knocked down a couple of more times since then.
Look, at the end of the day, we're just going to have to except the fact the the Marvel and DC Universes are fictional constructs. In those universes, there's such things as magic, alien technology, time travel, inter-dimensional travel and God knows what else. Gotham City was completely rebuilt after the events of No Man's Land. Coast City was rebuilt after the events of Emerald Twilight. If New York and Los Angeles were destroyed in the real world it would take decades to rebuild them assuming anyone had the financial means to do it.
Sometimes you just have to shut your minds off and try not to think about it. Go with the flow, as it were. Fans love their big superhero epics and that shows no signs of changing.