> The EU is big, the UK is comparatively smaller, guess what happens in a divorce? :)
A divorce seems an odd comparison to choose, but the UK has a large trade deficit with the EU. If the UK leaders had a backbone, they would walk away or be tougher in negotiations.
> 2. See 1. Also, there have been compromises, the UK wants to get unicorns. Full access to the single market yet no freedom of movement...
Do you have any examples?
Why should the idealogical idea of freedom of movement be linked to an economic market? This is an EU idea, and the separate of the two is not a unicorn. See: other trade agreements.
If the UK wants a simple trade agreement then it can have it. But that's not what the UK wants. The UK wants an open Irish border, an open border between Northern Ireland and the main island, but without submitting to EU regulations on goods. That's impossible.
Single market without freedom of movement is possible, but the thing about the EU is that different countries disagree about what the good parts and the bad parts are. Austria, if acting alone, might be willing to agree to single market without freedom of movement, but Poland is not going accept that. And so on. If you compromise with everyone, well, congratulations, you've joined the EU.
The EU is willing to negotiate a trade agreement. The UK wants that trade agreement to include full access to the Single Market, without freedom of movement. That's an unicorn.