We could do it. We'd have an ability to jump ship any time they tried any of those sort of tricks. Hopefully this stalemate would keep the evil EU racketeers behaving themselves.
The bigger problems are that they'd have wanted a ton of money per year from us, for basically doing nothing, i.e. extortion. And that they had a red line that we were not allowed to be better off outside than in, so they had a vindictive attitude towards us, which is definitely not where any sensible negotiations start from.
So, despite our constructive attitude, it quickly became apparent that achieving any sensible compromise wasn't going to happen. So we had to go all-out divorce on them.
We decided to leave, the EU decided it would be a bitter break-up rather than a constructive partnership.