Another problem is that most personalized coups are normally based on specific angst. Thus, let's say i hate how Macedonia subjects certain groups to unabated oppression. If i have the money i may seek out groups that i 'feel' would be good for Macedonia if they took over, and give them financial assistance. The problem with angst (as well as outright vendettas) is that the 'child with a new toy' syndrome soon pops up. Basically the coup is only effective until they take over (that is assuming they are successful). Once the government is toppled then what? Just because a group is comprised of successful usurpers does not mean it is comprised of effective leaders. To usurp and to lead are two different things altogether.
Now, imagine a worst case scenario where a George Soros character has a personal angst. To be honest with you i am surprised such things have not happened more often. A couple of billion (or even a few hundred million) burning a hole in one's pocket can make certain activities quite appealing.
And governments quite often abuse their citizens. But, with a personally-financed coup, there is a much shorter chain of command to go through to get results. If Coup Dictator A doesn't improve conditions quickly enough, then along comes Coup Dictator B to fire him and take over. This is what I mean by a democratization of the governance process. No elections to mess with, no pleading to one's representatives for change, etc. Simply remove A, install B, and get on with it.