Nothing that Theresa May can offer the DUP will satisfy, reckons Northern Ireland specialist Jon Tonge: Even turning up on bended knee with another billion pounds won't do it
So that leaves three outcomes: trying to get a better deal from Brussels; a general election; or a second referendum. (One might add a fourth: a Brexiteer Conservative PM who goes for a 'Dunkirk spirit' no deal).
The DUP has not really done anything to enhance sympathy for Northern Ireland in England as they appear to be intransigent and backward looking. No doubt they would say they are protecting the interests of their constituents who continue to return them with (in most cases) big majorities. However, more vision might protect their interests better in the longer run.