This is very logical and makes a lot of sense to me, however the leave side won last time by mainly appealing to peoples emotion and not to logic. They reasoned very early on, before the campaign began that they would not win many votes by talking about the financial side of things. Instead they concentrated on immigration and abstract things like Sovereignty things that people feel rather than think logically about.
They would likely do the same thing again, plus they would play the establishment stitch up card once again, I think the campaign would become very bitter and nasty. The far right would almost certainly try and organise street protests. I think it would be a huge risk to opt for another referendum with all that could entail.
I really don't like May, I don't like her deal, but I can't see another option that does not lead to an awful lot of trouble. Do I wish we never had this vote, of course I do, but we had it and 52% of people who voted, chose leave. May can say her deal gives leavers quite a lot of what they were hoping to get while at the same time avoiding a hard Brexit.
I suspect if she can get one or two minor concessions from the EU, she might garner enough votes to get it passed, perhaps on a second attempt. If she can't get it through then what other options are there, bearing in mind we leave on WTO terms the end of March.