Re: Damned if you do...
An election would solve nothing at this point.
The Tories would win (because Corbyn is just that frickin' hopeless, and the Remain vote would be split between Labour and Lib Dem). They'd accept this gleefully as a mandate for hard Brexit, and that would go through. (Step 1.)
Then the Tories would take their "mandate" and continue to misgovern the country for another five years, based on policies that no-one even noticed at the time because they were buried under the great steaming pile of ordure that is Brexit. Meanwhile, everything bad that happens will be blamed on some combination of (remainers/traitors/saboteurs/inevitable transient correction after Brexit).
Or, let's imagine that Labour and Lib Dem could do a deal (which seems improbable, given Labour's recent efforts to purify itself of all heretical liberal thought, but let's go with it), and put together a coalition government. Then it would be tasked with negotiating a New and Better Brexit, per Labour's policy, but doing so from a position of "no matter what happens we can't leave with no deal". This means the EU has even less reason than it's had to date to negotiate seriously - from its point of view, the whole problem can be solved by simply forcing the worst imaginable deal onto Britain, so that it will be rejected and the UK will remain. And then Corbyn, or his successor, will be in the position of trying to deliver on Labour's manifesto (which assumes Brexit) while still inside the EU, which would be mostly impossible, so they'll be epically punished for it at the next election. (And the Lib Dems would be even more screwed than they were with the Tories.)
OR, imagine that Corbyn could pull off - what he pretended to pull off in 2017, another massive swing to Labour, giving him an outright majority. (Spoiler, he can't. Lest we forget, he lost in 2017.) That leaves him - well, actually in the same position as if he'd done a deal with the Lib Dems but with one less scapegoat.
There's no happy ending to this story. Brexit is happening. If, three months later, you can still walk down the street without having to step over corpses, buy mange tout in Waitrose, turn on the lights - it will be called a howling success, because that's how low Remainers have dragged the bar.