While your skepticism is warranted, I would guess that the Dem’s refusal to let this Russia thing go - including the attacking of Barr - pretty much forces Barr to go all in on this investigation. Barr is now defending his reputation as well as the Office of President and the future integrity of the Justice Department, FBI, and CIA. Don’t think that Barr takes this lightly.
CIA Director under President Obama, John Brennan
Barack Obamas CIA chief, John Brennan, told the Annual Legislative Conference of the Congressional Black Caucus, on 15 September 2016, in Washington DC, that when he had applied in 1980 to join the CIA, he admitted to them that in the 1976 Presidential election, when Jimmy Carter was running against Gerald Ford, Brennan had voted instead for the candidate of the U.S. Communist Party, Gus Hall, and that he was then greatly relieved to find that this information didnt cause rejection of his CIA-application.
This had happened 11 years before the 1991 end of the Cold War...
https://moderndiplomacy.eu/2018/03/31/john-brennan-voted-communist-in-1976-then-entered-cia-in-1980/