If a person is so pro-abortion that it is the single basis for their vote, what will pandering do to win that vote?
Trump might support restoration of abortion at the federal level to 16 weeks (he has talked about this multiple times).
But Trump will not support abortion anytime, anywhere for any reason.
A fanatical pro-abortion candidate will still choose Biden, regardless if Trump moderates on the subject.
Yes, the complete fanatics are unreachable, but there are women along the spectrum whose votes are winnable or losable as they weigh the issue against others.