What's the structural problem at play here? Brexit is definitely isolating, which promotes "comparative disadvantage", i.e. doing things domestically that are more efficient to achieve through trade.
Maybe there are demographic problems? Too many elderly, not enough youth and skilled labor?
They allude to democratic inefficiencies, i.e. voting blocs that receive more than they pay, creating poor allocation and disincentive.
But all of the above don't seem to be solvable. UK won't re-enter the EU, demographics can only be tweaked by immigration, and voting blocs are part of democracy.
So what does that leave in terms of solutions?