This point raises the other side of that coin... inasmuch as there are "Trump voters specifically" who will go back to non-voting once Trump is no longer a candidate, there are probably also "anti-Trump voters", who will similarly go back to non-voting once Trump is no longer a candidate to vote against.I think a sizeable number are going somewhere: back to being non-voters. They are Trump voters specifically. He's sold them on this "I'm persecuted by the elites in American society just like you are" line. They identify with him personally, not politically. And they will be uninterested in any one who is "just a politician."
I don't know that the two contingencies necessarily cancel each other out, however... my hot take is that there would seem to be alot more anti-Trump voters than there are Trump-specific voters... so the exit of Trump may ironically end up costing the Democrats a lot more voters than the Republicans.