Re: Brexit got done
The UK could have had a single market deal of its own. That was always on the table from the EU side. I would mean no NI border issue, so no NI protocol. It would also have avoided customs checks between the UK and France, avoiding the motorway queues of trucks we have now, plus all the time-consuming paperwork.
The UK would not accept the single market principles, in particular freedom of movement, so would neither have joined EFTA nor accepted a single market deal. That was why the promised cake did not materialize. Because the UK government decided that "leave" had made a bunch of promises, but as "remain" said, they could not have single market access and end EU immigration as they claimed. They chose to pander to the anti-immigrant right, rather than the pro-business centre, and the rest is history.
In 5 or 10 years, once it is clear that Brexit cannot be made to work, and that the growth and trade friction cannot be offset by trade deals outside of the EU, the UK will eventually sign a single market deal, and be bound by the rules. There is no other reasonable choice from an economic standpoint, and the benefit after several years of trade disruption will be an easy win for whichever party eats humble pie and admits that the UK needs the EU more than the EU needs the UK.