why wouldn't they? are you REALLY that naive? the EU has been intransigent during the negotiations... they have put nothing on the table insisting that WE come up with the terms... and everytime we have they have said "No, Non, Nein".
Because we are the ones that want to leave, that's why we have to come up with terms. They've offered us all sorts of options, but the UK's ridiculous red lines put paid to all of them.
The backstop ensures that, as much as possible, trade across the Irish border continues as it is. If we agree a deal where that can continue, whether that's now, next year, in 2021, or 2055, the backstop is not needed.
...please please PLEASE give me one bit of concrete proof that they will EVER agree to that?
The fact that they accepted the UK's notification under Article 50, for a start. The UK didn't HAVE to negotiate anything, we could walk away after two years and go straight to WTO. If the EU weren't going to accept that, they wouldn't have accepted the notification.