Shropshire's Industrial History

Why did Shrewsbury, the 7th richest town in England (outside London) in 1334, become a retirement settlement?
Why did Shropshire, maybe the most industrialised district in the world in the early 18th century, become something of a rural backwater?

When researching folklore in Shropshire, I became acutely aware of how changing economic fortunes had shaped the County.
Much of this cut across what I had been taught at school in Shrewsbury, that Shropshire had always been an agrarian economy and Shrewsbury a middle-class town, being closer to Sailsbury than Stoke.

I must emphasise that this is a broad-brush analysis, which by its nature ignores the important details and nuances.
It is also a highly personal analysis, but one of a proud Salopian not that of a detractor.