Britain is still a member of the EU thanks to people who wished it wasn’t. Brexit has already been delayed once because MPs who think it should happen voted against the deal that would have made it happen. Now Theresa May is going to Brussels to postpone it further. Such self-thwarting is a feat of slapstick political gymnastics, like falling up a flight of stairs.

Eurosceptic hardliners don’t see it that way, of course. They believe that May’s deal does not qualify as a proper Brexit, and would rather leave with no deal at all. They also think parliament is stuffed with Europhiles who are obstructing our departure. Even then the logical thing for the ultras to do is vote for May’s deal, then resume agitating for harder severance terms. The no-deal scenario is a fantasy anyway, a utopia of pristine liberation. As such, it can be revived within days, or indeed hours, of a deal being ratified. Some of the more tactically astute Brexiters have understood that, and their cynical pragmatism is causing a split within the Tory European Research Group; the cold-blooded fanatics are falling out with the hot-tempered maniacs.

It isn’t even true that parliament has a blocking majority for remain: 498 MPs voted to trigger article 50, with only 114 against. Support for a second referendum is a crude proxy for remain sentiment, and that scored 280 when MPs held indicative votes on rival schemes earlier this month. That leaves a pool of around 360 who accept that Brexit in some form should go ahead. If they were capable of all walking through the aye lobby at the same time, Britain would by now have already left the EU. They aren’t, so it hasn’t.

One obstacle is Labour MPs who want Brexit out of the way but can’t endorse anything with Tory branding. That problem isn’t likely to be overcome in talks between senior Tories and Jeremy Corbyn’s team. The prime minister’s fear of destroying her party prohibits much blurring of red lines, and there is not much incentive for Corbyn to take co-ownership of any plan. He would have to vote for it alongside May in the Commons, defend it in public, and withstand cries of betrayal from traumatised pro-European members of his party.

The uncompromising character of the two leaders is a problem that could be overcome if the rewards for compromise looked good enough. But the return on investment in a soft Brexit is poor, and it gets worse over time. It sounds virtuous when the alternative is ongoing crisis and deadlock. And in theory there is a position somewhere between total rupture and return to the bosom of Brussels. In those indicative votes, a customs union scored a respectable 273. The super-soft “common market 2.0” idea wasn’t far behind, on 261. Both numbers would have been higher if every MP who could live with each of them had voted for them.

The appeal of the soft route is that it avoids the economic pain of a hard Brexit and the political trauma of trying to abort the whole thing with another referendum. It offers pro-Europeans some continuity, while legally terminating EU membership. But those advantages decay quickly. Both remainers and leavers would resent the cost of what they had surrendered more than they would cherish their consolation prizes. It is Brexit for people who don’t like Brexit, which is an ungrateful market. Britain would be locked into a sullen and voiceless orbit around Europe’s decision-making institutions. The old Eurosceptic myth of Westminster taking dictation from Brussels would no longer be so paranoid. The pattern is already visible in May’s demeaned status as a supplicant, begging for article 50 favours from continental leaders she should count as equals.

Whatever the terms of a compromise deal, hardline leavers would immediately take up the cudgels for harsher separation. Ex-remainer MPs would struggle to defend arrangements that they had endorsed only in a vain attempt to bring closure, while nationalist radicals would exploit that ambivalence to prise the old wounds open. A soft Brexit would be a pitiful foundling plan, abandoned by its political parents. No party would take it in. But, quite understandably, decent, fair-minded MPs are wilting under the pressure to deliver something – anything – so they can call Brexit done. They are rightly attuned to the frustration of leave voters. In a febrile climate, they worry that a European parliamentary election campaign, a likely condition of article 50 extension, would turn ugly.

There are worse things that could happen to a democracy than its citizens being given an opportunity to vote. The same goes for a referendum. And the alternative is a duff deal, soaked in panic, nobody’s first choice, bundled through parliament by a coalition of demoralised remainers and disingenuous leavers, the former with heads bowed, the latter with fingers crossed. That wouldn’t be a durable compromise, or even a truce. It would be MPs bailing themselves out, borrowing a moment of respite for which the country would then pay in years of disappointment and bitterness. Even if a majority could be found for a Brexit settlement, this parliament lacks the authority to validate it as a good deal in the public eye.

As the article 50 countdown has neared zero, politics has been consumed by the question of how to avoid the worst outcome, with contradictory accounts of what that means: no deal, a referendum, a Corbyn government, Boris Johnson in No 10. A cacophony of partisan calculations has drowned out more essential questions that need revisiting three years since the Brexit decision was first taken. What does it really achieve? What does it cost? Is it still worth it? There isn’t a clear Labour or a Conservative answer to those questions, which is why May and Corbyn seem to prefer politics when it is about something else. But the questions won’t disappear. If they are not asked in another referendum, they will be asked by subsequent generations, amazed that we went ahead without one.

• Rafael Behr is a Guardian columnist