10 years ago i bought a 24MP Nikon d3x. At that time the only 24MP DSLR camera.
If you had started this topic then, everybody would have said 12MP is more than enough, ...
No, not everyone would have said that, since some were already using well over 12MP (Canon was at 17MP 15 years ago and at 21MP 12 years ago), some were at over 24MP, for example with MF or scanned film, and some were aiming far higher, for the pixel counts needed to match large format film.
"Is 24MP all that most interchangeable lens camera users need for most purposes?"
maybe, but that is not of interest to any photographer; It is only statistics.
It is very much of interest to photographers choosing a camera and a system, looking at trade-offs of resolution, frame rate, dynamic range, cost, weight and such.
It all depends on what you think you need to get the photo you want to make.
Exactly; and the desired amount of resolution is one of the factors in that, as you show with your comment that "24MP was just right for me."
I know some very fine photographers that need only a pinhole camera, others need an MF.
Indeed; no one is disputing your point that _some_ significant number of photographers have a good use for MF or 47MP or 100MP or 150MP or whatever. But how many times do I have to explain the difference between "most" and "all"? Your reply seems like several others which start from the undisputed fact that "Some of us need more than 24MP" and then object to my question as if I am denying or denigrating that need.