Substantial Brexit progress was never on the agenda for the EU’s Salzburg summit in Austria, so its absence comes as no surprise. More revealing is what the gathering says about the balance of power: European leaders can send Theresa May away humiliated and empty-handed, and still imagine they have done her a favour.

May was given 10 minutes to address her fellow heads of government over dinner last night, but no subsequent discussion was permitted because, formally, Brexit terms are negotiated with Michel Barnier and the European commission. Any British hopes that those lines might blur at Salzburg and more productive channels might then open up behind Barnier’s back were dashed. Concluding the summit, Donald Tusk, the European council president, re-affirmed member state solidarity behind the commission process. He also said bluntly that the economic aspect of May’s Chequers blueprint for Brexit “will not work.”

The prospect of, say, Boris Johnson emerging as his party’s champion is sufficient to focus minds in Brussels

None of this looks like the diplomacy that was promised by those hardline Eurosceptics who insisted that the EU needed the UK more than the UK needed Europe. There would be cake to have and cake to eat; the negotiations would simply be over the colour of the icing. Instead, the raw arithmetic of 27-to-one asserted itself. The prime minister’s advocacy of the Chequers plan has become a plea for mercy, although Tusk politely pretends the relationship is more balanced than that. European leaders can see how little room for manoeuvre May has in parliament and with her party.

The timetable for Brexit talks has been stretched to swerve around the Conservative conference coming up in Birmingham, but not by much. Talk of an emergency summit in November, allowing some slippage from a scheduled deadline in October, sounded more provisional from the EU side than it does when UK officials have been organising their diaries.

The British side had also hoped that some friendlier theatrics might have been staged at Salzburg to present May as the tough negotiator – some choreography of clash and concession to advertise the prime minister’s effectiveness. But there is a gap between what EU leaders think is a compromise with May (hinting that some kind of bespoke deal could yet evolve from Chequers) and what May can exchange for hard political currency back home. And on the substance – specifically the Irish border impasse – they cannot pretend there is progress if there is none.

May’s weakness in Westminster still gives her one point of leverage in the negotiations – the alternative to dealing with her with little time to spare, is dealing with someone worse with no time at all. The prospect of, say, Boris Johnson emerging as his party’s champion from the rubble of a collapsed Brexit process is sufficient to focus minds in Brussels.

Some EU officials and leaders see the risk that constructive British engagement with the European project could die along with May’s premiership. They see a messy Brexit provoking a lurch into something more like marauding, anti-Brussels, Trumpian nationalism. A faction of the Tory party is already saddling up for that journey.

There is also the prospect of another referendum coming into focus over May’s shoulder although she pretends not to see it. In the past 24 hours, both the Maltese and Czech prime ministers have made encouraging noises about Britain reconsidering the whole Brexit enterprise – and being unanimously welcomed back into the fold. That might be overstating it. Across the EU there are many pools of sorrow at the UK’s 2016 decision to leave, but there are also now strong currents of impatience. Much goodwill was frittered away in the period when Tory ministers were making ludicrous Brexit pronouncements at home and offering nothing sensible abroad.

There is also anxiety about the integrity of the European project that discourages anything that might look like a reward for splitting the union. This view – short-sighted, perhaps, but potent – holds that Euroscepticism must be seen to end badly for the country that has taken it furthest. But the punitive urge is not paramount. In Berlin and Brussels, the capitals that still largely set the tone on Brexit, the emphasis is on getting the UK safely off the premises, not on finding ways to hurt us or keep us in.

For now, May is the person with whom European leaders have to do business. But, more important, given the alternatives, she is also the person with whom they want to do business. The EU collectively has no interest in undermining or humiliating the prime minister. At the Salzburg summit it didn’t look much like May was getting any favours, but these things are relative. From the continental point of view, she was shown patience, she was indulged.

Ultimately the EU cannot give May what she really needs, which is a Brexit model that will simultaneously satisfy the whole Tory party and win support from a majority in the Commons, without inflicting harm on the country. They cannot give her that because it doesn’t exist, never did, never will.

• Rafael Behr is a Guardian columnist