The Backstop only became part of the Deal because of the UK's own negotiating position, in particular with respect to a desire to leave the Customs Union as soon as possible. The EU initially proposed a UK-wide backstop, which is more or less a suggestion that if we can't do a trade deal in time then let's just keep the old rules until both sides are ready, and this was rejected. The EU and UK then agreed that the mean problem is the Irish border, so reduced the backstop arrangements to just Northern Ireland.
In that sense the Backstop *can* be dispensed with, but only if the UK accepts either that (a) they won't leave the Customs Union, at least not for the time being, or (b) they will try to leave the CU by seeking a new set of trading arrangements, but if a new deal isn't agreed then there's a UK-wide "backstop" until there is.