“I agree, I don’t get it, why would anyone care to do this climb?”
If you’ve ever been at a point in your life at which you feel lost and demoralized, based on issues that are out of your control, and you feel that you need to do something, anything, to put a punctuate mark in your life from which you can move on and reconsider, you can understand doing something like this.
I’m not saying that’s why most do it, but there is something about the enormity of the task, and that danger, that strips away the everyday concerns that are clouding your ability to see what’s important and what the real value of your life is. It’s good sometimes to be reminded just how small you are, and therefore how small some of the concerns you have are.
On the other hand, if you have a family and people who you are responsible for, it’s a bit irresponsible to do something like this just for an ‘adventure’.
I strongly suspect a large percentage of those who do this are guys with too much money looking for bragging rights.
A more extreme version is climbing the highest point on each continent.
Everest is not, BTW, a particularly difficult climb technically. There are much harder ones. The difficulties of Everest mostly involve weather and altitude, which are quite sufficient to make it sufficiently dangerous for almost anybody.
Good analysis in your post #34.