I fear that it's more complicated than that, it's not simply too late but too fake. People have been taught to dislike the EU and other European countries, they are happy to blame continentals for every thing and remaining or a soft Brexit won't change that, the ingredients for Brexit are still there and they will come out at the first opportunity whether it is because the economy isn't great or because the UK want a particular deal/arrangement.
I have been in the "it's better if you stay" camp, from the beginning but thinking about it, it's a terrible idea and a very naive one, we don't trust you and you don't trust us, we are not on the same side and no amount of pretending will change that. A painful break is better than a poisonous relationship, we should both take the hit and move on.