Why haven't Russian oligarchs overthrown Putin yet?

The balance of power is not in their favor. Putin started as a protege of one of them, Boris Berezovsky, who was very tight with Yeltsin’s “family”. Then he fought Berezovsky and won. One by one, he repeated the same with all the oligarchs, leaving those who are content to operate in the private sector and stay out of politics. That was one of the major reasons for his popularity, as the oligarchs were quite hated by people. His tough stand against the US is the other. [Note: Yeltsin was placed there by us, aka  the CIA. He jacked up the oligarchs, and from the vast readings I've done, Putin totally opposed him AND took down the oligarchs, as I've posted about in the last year, several times.]