Not just blackmail, likely not even predominantly blackmail. They paid people, widely and prodigiously. They needed lots and lots of money, power and access to keep that going...hence the Foundation and pay to play. And selling out America in a very big way.
Their power (position) is waning, their access is waning. And the big money they need to pay so many, so handsomely is gone.
Thats whats changed. Its the money from selling out America that they used to buy people, their work and their loyalty. All gone.
Makes sense.