The majority in parliament clearly wouldn't put through the true essence of Brexit so cross party talks would have been completely pointless. They simply don't accept the result of the referendum. It's undeniable.
It is MPs duty to represent the people who voted for them, they were chosen by their constituents. The advisory referendum taken 3 years ago should have no sway on MPs who were voted to represent alternative views more recently.
They don't have to accept the result because it was superceded by a general election, and it's their duty to uphold the values for which they were voted in. Doing anything else, for any reason, would be a betrayal of democracy (though it remains common).
One of the pillars of the leave campaign was to restore parlimentary sovereignty, what better way to show that parliments power is supreme than MPs upholding their values and standing up for the views they were voted for. Frustrating the process, largely for good reason, has shown the power parliment weilds over the country.
The leave vote is divided, the remain vote is divided, there is no majority for any way forward, no party has a majority either. Therefore the only solution (and only way to deliver brexit in a democratic way) is to remove the threat of 'no deal by accsident' by delaying brexit and calling a general election.
£75 billion spent on creating this mess so far, with no end in sight. Our constitutional crisis continues.