This is the Maria Therese chapel at Schönbrunn Palace in Vienna. I wasn't supposed to be where I was to take this picture, but there was no one around to tsktsk me and what's the harm? But it does show that you have to keep an eye on photographers every second or they'll just ramble all over the place.

Note to anyone going to Vienna: the Schönbrunn Palace is a mass tourism machine designed to extract your money. Worth seeing but only pay as little as possible with no extras. Off season all the flower gardens for example are nothing.
I was at the Belvedere on a day it was open late. Not the same thing (more of an art museum), but much better experience. Also a lot of other palaces around Europe, like the not hugely touristed Würzburg one. And other amazing old churches and chapels of course.
It is amazing how they extracted wealth from the peasants and colonies etc. to build these palaces and churches while the peasants had nothing, but then a couple people own half the wealth in the US and our inequality is way worse than in those European countries today.
Interesting. I am in no way disputing your point -- I'm just interested to see how much things have changed. Fifty+ years ago, when I backpacked around Europe, Schoenbrunn Palace seemed like a hidden gem -- not expensive, not crowded, and very much a place you could take your time to appreciate. It stood in stark contrast to Versailles, which -- as you put it -- was very much a "a mass tourism machine designed to extract your money".
Same experience I had. I also visited Vienna including the Schönbrunn Palace back in the olden days. There are of course 10X more tourists everywhere than there was back then.
One place that has adapted well to this is Mount Vernon, which is not a NPS site like you might imagine. The house isn't that big but they run the tourists through assembly line fashion. On the way there are several kinds of films including one where it snows on you (the Valley Forge Experience! - at least the last time I was there) , and they have developed a lot of other stuff on the property to explore including, like many other such sites, some slave quarters.
Last time I was in London I finally went to the Tower of London. It was early spring and the back-and-forth Disneyland type line barriers in front of the Crown Jewels building were empty. So Lesson 2 is going to famous stuff off season.
Wo kein Kläger, da kein Richter.
Literally: where there’s no plaintiff (complainant), there’s no judge.
Figuratively: no harm, no foul.
Several years ago, I was briefly a guest at one of the colleges at Oxford. While I was there, I wanted to poke my nose into the chapel for a few minutes. I asked one of the porters (those are the folks who keep things running, including as a kind of security force) if it would be all right for me to go in. He said that would be fine. Then I asked if I could take a photo. He said no, that was not allowed. Then he said, in a classic working-class English accent, "Of course, if you did, I wouldn't know it, now would I?"
Remaining bits of British humor (I mean humour) is one of their best features.