As the UK political class zigzags towards the abyss, saying one thing about Brexit today and another thing tomorrow, any illusions in EU capitals that the summer holiday may have brought British MPs to their senses must now be put to rest. Indeed, the daily British displays of hope for a sweet “soft Brexit” deal illustrate not only the tenacity of British self-delusion. More than that, they lay bare a persistent and dangerous ignorance of the internal logic of the EU.

Talk in British media and politics is still too often of the need for a “tough negotiator” who can deliver a great deal for Britain, keeping the benefits of single market membership without any (or many) of the obligations and costs. What is required, so the thinking goes even in most remain circles, is an acceptance on the part of the EU that it is in nobody’s interest to “punish Britain” in order to “discourage other countries from leaving”.

The first problem here is the term “single market”. Brexiteers and remainers alike seem to cling to a 19th-century notion of separate nations making their own products and trading them with other countries. The chief political project is then to lower or ideally abolish tariffs so that the so-called comparative advantages of free trade kick in.

Last week chief EU negotiator Michel Barnier called this view “nostalgic”, and for good reason. The EU is rapidly evolving into something far more ambitious than just a free trade area: it is in the process of becoming one huge economic zone governed by a single set of rules and standards and overseen by a single European court of justice, striking trade deals with the rest of the world and deriving its logic and coherence from the four famous freedoms of goods, capital, services and labour. Products such as cars, computers or aeroplanes are now built from components made in factories and production units scattered across the EU, with employees moving seamlessly between them. For this reason “single economy” is a far better term than “single market”.

The refusal or inability to see this goes a long way towards explaining the British misreading of the EU’s position on Brexit. It is true that in the context of Brexit, EU member states want to discourage one another – but not from leaving the EU. There is not a single other EU country that wants to leave, because each believes the benefits of membership to far exceed its costs. But this is not to say that each member state would not love to tweak a few rules it finds irksome, to claim a few extra benefits and rebates for itself, and to shirk some obligations.

What EU countries as well as EU officials in Brussels therefore do want to prevent at all costs is member states using a sweet deal for Britain to claim their own version. With 27 countries demanding exceptions, special arrangements and opt-outs, the unravelling of the single market or economy would be all but assured.

This is what the EU means when it insists that the “integrity” of the single market trumps all else. The EU’s refusal to cut Britain a deal and protect it from itself is not about punishment. It is about self-preservation. For this reason most European business groups support the EU’s position, with the loudest voices in this camp often coming from the German car industry – the very sector that Brexiteers promised would push like no other for Britain to get a sweet deal.

Brexiteers are right to argue that the EU will let political considerations be trumped by economic self-interest. Where Brexiteers go hopelessly, disastrously wrong is to think that EU countries’ economic long-term self-interest is served by a special deal for Britain.

The fact that on a rainy day in June 2016 millions of British citizens voted for a “have our cake and eat it” option that simply isn’t on the menu is terrible. But it is not the EU’s fault. Britain’s political establishment failed those voters miserably by never laying out for them the options that were actually on the menu before asking them to vote. Yes, doing so would have meant open war with the billionaire-owned press. But then again: what is a politician worth who does not dare to speak truth to tabloid power?

To be sure, the EU will be damaged if in 18 months Britain crashes out of the EU, the way your suit is ruined with blood stains if the person standing next to you decides to shoot themselves in the foot. But does the British political class genuinely believe that EU member states are going to jump in front of that bullet and undermine the very existence of their single economy in order to safeguard the privileges of a country that over the past decades has lost no opportunity to disparage, undermine and blackmail them? Britain already had a sweet deal – it’s not getting any sweeter.

In spite of its recent bout of ignorant irrationality Britain still has many friends and admirers across the continent, and friends don’t let friends drink-drive. But what if the inebriated party insists that you are no longer friends in any case?

• Joris Luyendijk is an author and journalist