Given the last couple of months, I think there's no evidence at all to support the assertion that British politicians aren't idiots.
Ignoring the legalities, the Leave vote crossed the Rubicon.
The EU has always tolerated rather than enjoyed the company of the British establishment. So the EU is happy to see the back of the UK.
The British establishment still thinks it's the 19th century, so it's happy not to have anything to do with the 21st.
The biggest loser will be the City - which is beyond ironic considering the UK has literally spent the last few decades retooling its economy around the City. Now it's about to throw that away.
We're not great at much else. The things we are good at - culture, R&D, farming, tourism - all work better in the EU than out.
In practice, immigration is a meaningless non-issue.
Getting rid of Polish plumbers won't suddenly reveal thousands of competent English plumbers hiding in a cupboard somewhere. It takes time to train people up, and the biggest source of training money has been the EU.
It takes time to rebuild manufacturing, and the biggest source of funding for rebuilding manufacturing has been the EU.
It takes time to improve education, and the biggest source of funding for improved education - especially at postgrad level - has been the EU.
We could move towards becoming a startup economy, but if all the VC money moves to Europe, we won't have the money to do it natively.
The Leave vote is possibly the single most stupid decision in all of British history.