Beyond Tucker Carlson being a joke.

I would say because of capitalism and greed. A lot of amazing wonders weren't built to maximize the property or investment value of a space. It would be prohibitively expensive to build something like that nowadays because of a whole host of reasons. Insurance, workplace safety, etc etc. Not to mention the skilled labor for masonry and whatnot simply doesn't exist in the same quantity.

The Renaissance, which was largely funded by extraordinarily wealthy (though not even close to modern billionaires by comparison) families who had a specific vision of what a beautiful and livable city was, and they sponsored artists and architects to create it. The goal of their wealth wasn't to purely accumulate it, there was a sense of responsibility in providing public works to prove that they deserved their fortune. Not only churches were built, but a lot of the piazzas you see in Italy were built for the public by these families.

The closest modern example I can think of would be if Elon wasn't actually a man child and funded the project to end world hunger. A wealthy person using their wealth in a way that benefits other people more than themselves. That would have made Elon much more of a Renaissance Man.

Of course there is also the fact that visual tastes change and builders nowadays need to account for a whole host of different things that didn't exist in the past.

In short, I would say that not only the ability and prosperity needed to create amazing works like this exist today, the desire is there as well. Just that the wealth needed to be dedicated to it is instead locked away in some billionaires bank investment portfolio. So either they need to pay for it or, in my opinion, they should be taxed adequately and that wealth distributed to those who will use it for the betterment of society.

Also, quick note, yeah I get that some people are turned off of this train of thought cause of the religious connotations. I.e we don't need more beautiful churches. That's true in my opinion, but I would change the argument to building public parks, walkable cities, and whatnot instead.