I assume it's a natural thing to happen if somebody gets a lot of power. If not being extra careful, they will automatically get surrounded by yes men and start drifting in odd directions. Happens to dictators too.
With democracy at least there's changing some of the people in power on a schedule.
It's not yes-men. Power and money tend to convince people they are successful in every aspect of life. Our society emphatically endorses this viewpoint and even idolizes it. Look at our celebrity/businessman worship.
Then, since they are rich, anything they do is now acceptable. Anything they do is what a successful person would do. That becomes their viewpoint.
As this phenomenon is so common, do we have enough science about it to make it a base for laws, so future generations could avoid this state of collective psychosis it seems to lead to?
As soon as I personally attained a modicum of financial security I automatically started giving fewer fucks about things than I used to. I assume the number of fucks given (about people, ideas, values) asymptotically approaches zero as your wealth increases. Or at least it does if you don't work at it.