Bush is the first President that got to see the mechanics of leaking from the underside, when he was working in Daddy's Admin. A lot of Bush 41's staff was busy scoring points with the media by leaking, and fool enough to assume that Bush 43 was a dumbo who could not pour sand out of a boot if you printed the instructions on the heel. And Bush 43, who has never been afraid to let someone underestimate him watched and listened. And took what he learned to his administration.
It ain't just Dems that underestimated the man.
It also helped that he pulled in a lot of outside the beltway talent, ignoring the political mercs of DC that use leaks and other illicit favors as common currency with the media and lobbiests.
Now to shovel out the rest of the smelly barn and flush the remaining x42 appointees and the bulk of the top civil service management loaded with traitors and deadwood.