CuriousaboutSamphire - where the hell did you get the idea we lose our current carve outs if we revoke Article 50 and remain? Ever since the EU said we can revoke Article 50 unilaterally, without any input from the rest of the EU, it has been the case that we can go back to the status quo, including all our rebates, etc, etc. We won't have to renegotiate anything, we just stay as we are. It's only if we actually sign a withdrawal agreement that there's no going back without fucking ourselves over.
And what makes you think "the rest of the world" trades on WTO terms?! Nobody does that if they don't have to - they negotiate better terms if they possibly can. Why do you think £12million of taxpayers' money has been spent on a swanky Manhattan apartment to negotiate trade deals in, if the UK is so bloody delighted about the idea of trading on WTO rules?!?! Arch Brexiteers are convinced they are better at negotiating trade deals than the EU is - they do not want WTO rules. They think WTO rules are just acceptable collateral damage for the next 10-15 years (they pretended they'd have loads of deals done by now already, but that's not proven to be the case), because despite all evidence to the contrary, they think they would make good negotiators and jump to the front of every negotiating queue 
. And the fact that the two international figures most supportive of Brexit when we had the referendum were Trump and Putin is apparently not supposed to freak us out at all, because we know how friendly they are to smaller, weaker countries 
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If we leave the EU, big business will be fine, although it might move its bases out of he UK if it looks like the UK is crap at running itself, as it will no longer have the advantage to them of being part of a massive trading block. Smaller businesses (which largely trade domestically and with other EU countries) might realise they cannot cope with all the new paperwork involved in dealing with their neighbours these days and go belly up before better terms are sorted out. Obviously, the City will rake in huge profits one way or the other, which is why several of the arch Brexiteers have backgrounds in, or strong connections with, the City of London (eg Farage, Rees Mogg and Johnson) and offshore funds if UK plc no longer looks like a good bet - it's a win for them regardless of the extent of the losses to anyone else. They really don't care what happens to the stability of the country or people's jobs in the next few years, as that is entirely acceptable collateral damage from their point of view while they personally enrich themselves and their friends. The rest of us poor idiots will be the ones taking the risks, not them. We're the sitting ducks.