Also, if our leader-caste couldn't be bought because they had moral and ethical values beyond and above rational self-interest (such as collective solidarity and loyalty to their own ethnicity before anything else f.e.), it wouldn't matter what or how much they were offered.

But since the 1970s, Randian values and the neo-liberalism and US neo-con values is the guiding principle in all western nations:

"Does it profit me - now - with little to no risk, and no real cost?"

That is a principle that can only come about in a sheltered environment by equally sheltered people, and can only ever lead to ruin.