Wales has a very serious problem with this degrowth mindset. Bristol is one of the UK's highest income cities, it's a very short journey from Newport and the M4 bottleneck chokes off much of the prosperity that could spillover.
I'm going to be contraversial. All those who moved to Wales but work in Bristol, knowing the problem of the bryn glas tunnels, can move back or put up with it. You had a choice, you still have a choice so stop bitching.