>Single common thread has to be poor governance.

I think a structural issue is aging demographics. Lots of welfare policies were enacted when the ratio of workers to non workers was much higher. For decades now, this ratio has been getting smaller and smaller, hence the constant political dilemma of which benefits to cut and how much and for who.

The UK seems like it will especially struggle with delivering universal healthcare promises, as well as pension benefits. Not only are fault lines along rich and poor, but they will be more and more along old and young.