We do have devolved powers, so Scotland and Wales* have functioning Regional Governments, with devolved funding from a formula that gives them substantially more money than they collect in tax.

So they should be doing great right? Wrong. They massively struggle and yet live in a "best of both worlds" scenario, they can run the health service, transport, taxation policy and all things that affect regular people without having to worry about the annoying stuff like defence and foreign policy. So why do they still have very poor outcomes? Look at the welsh NHS, it's horrific.

Essentially most of our productivity comes from London and the SE. That means by the way if you're smart and educated but grew up in the welsh valleys, the first thing you do is move to London/SE where all the jobs are. Can Wales attract a google office to Cardiff when all the talent is in London?

*NI is a long story.