And with the tight feedback loop between committer and contributor along with working on a new feature instead of existing code leads to people getting commit privileges on the spot (if someone is there to give them the privileges; I honestly don't know who has the abilities to give the rights anymore beyond Barry, Martin, and Neal).
[I don't think Barry actually can/does provide these privileges]
I'd like to point out that there is a separation between the management privilege, and the technical implementation. Neal, Georg, and I do add committers to the database, however, we don't make the decision to add them. Instead, we (atleast I) try to sense consensus among committers, and then implement what I feel this consensus is. There can always a BDFL pronouncement, and also the release manager (i.e. Barry) can order that somebody gets commit access. In most other cases, consensus was fairly obvious.
In the specific case of Victor Stinner, there had been a few seconds, but none of the long-time committers supported him, so I did not add him (I was opposed myself as well). Now that he asked a second time, the opposition spoke up.