The voters now have a lot more information. They know the NHS claims were lies. They know which billionaires funded Leave. They know Putin had a hand in it. They know that the EU won't agree to the pie-in-the-sky one sided fairy-deal the Leave-voters have been promised for a few years now.
Why not hold a new referendum with more information and more precise choices?
The UK government doesn't have any of its ducks in a row, deal or no deal. They almost certainly will have a recession, they will almost certainly lose a good chunk of their financial industry. It's just a fact of life if you are on an island and suddenly choke your ports.
The alternative to virtually closing those ports (for lack of resources in screening) is to do no screening and just accept the EU standards. Now without having a say in those standards. Good luck...
Also, they're not dismissing parliament, but suspending it.