Added benefit of a Kamala win now is that she could run again as an incumbent in 2028 and that’s another four years that Alito and Thomas have to survive
The last time a VP won after their President's term was up was George H.W. Bush, and the time before that was Martin Van Buren after Andrew Jackson's term was up (both one-term Presidents, incidentally).
Like you need the combo of a two-term POTUS, who finishes up while relatively popular, and has a VP who is interested in the presidency, AND wins both the nomination and the election.
VP's who tried to run for election after the President's term was up:
Al Gore, 2000, lost general
Richard Nixon, 1960, lost general
Alben Barkley, 1952, lost primary
Thomas Marshall, 1920, lost primary
Adlai Stevenson (not that one), 1896, lost primary
John Breckenridge, 1860, lost general