This is all true. But it's easy for the EU at the moment, because they still hope that Brexit will fail. If a no deal looks likely, panic will set in. I'll give you an example. Simon Coveney, the Irish foreign minister was caught on mic recently admitting to a colleague that in a no deal, they will HAVE to set up a hard border, being part of the EU. But they can't admit to the Irish people that they will be the ones to put up this border.
If they agreed an end date to the back stop this could be avoided