Nobody who wants a second referendum has got as far as thinking about how on earth they would win one (barring fixing the questions, which wouldn't wash).
The Leave campaign would be the simplest to message ever: Look at these *******s! Look how they've ignored you and are trying to overturn your vote! Are you going to let them get away with that?'
The Remain campaign, on the other hand, would have two years of bitterness, enmity, threats and bullying from the EU to overcome.
Leave would win by a bigger margin.