I understood your original point and I disagree.

1) It isn't certain he would be removed by a PLP revolt, it could be the unions who demand an alternative, it could even be that more members turn against him.

2) The election will be lost in 2020, the point is by how much. A great leader could gain a few seats, a terrible leader could lose over a hundred. We can't risk losing so many seats just because Corbyn supporters want an excuse not to take responsibility for the damage he has done so far and would do in a general election.

3) It is pure conjecture that Jeremy Corbyn ceasing to be Labour Leader would lead to a moderate replacing him, it is pure conjecture that a loss at a GE of the replacement leader would lead to a resurgence of the hard left in the party. The situation you describe is uselessly hypothetical.

If you don't see the difference between a coup attempt later this year and a coup attempt after a 2020 General Election loss, you are part of the problem.

You don't have the gift of political foresight anymore than I do.