What you say is simply not true. Boris's team has continued to meet with the EU team at least twice a week. The EU side, so far, haven't shown any signs of being prepared to renegotiate the W.A. they have presented zero new ideas as far as we know. Unless and until they are prepared to renegotiate, we know that the existing W.A. stood no chance of passing the existing UK parliament.
After a general election, if we get a more Remain-supporting government, the EU still won't need to negotiate as they will be confident that the UK will then entirely remain. The Benn Bill has given the EU the incentive now to sit on their hands and wait for Remain - the only chance now for renegotiation is if the general election returns a leave-supporting government with a good working majority.