The Engineer did a salary survey in April this year that makes interesting reading: 

It does, but caution to the view that salaries in the US are twice what they are in the UK, the cost of living, medical, housing and exchange rate gearing hide that these are much closer than this looks. Also in the US, there is wide variation across the country - wider variation than it is between our South East and North West pay rates.

While your statement about regional scale is accurate (largely due to unionisation, or the lack there of, due to varying state legislation over the course of the country’s history), I have to disagree with your statements about CoL, exchange rate (a meaningless measure), housing, and medical. Most engineers who are earning double the salary have excellent healthcare coverage which is often corporate-covered in large part, live outside of a major metropolitan areas where housing is 1/4-1/2 the price (or less), and have enough surplus income to comfortably eat outside of the home as a family at least once a week. This does not include the luxuries they allow themselves, as most Americans do; and they are still happily saving with minimal concern for what’s in their checking account that day. As someone who was earning three times as much in the US, living in a place with a significantly lower CoL (at least 30-40%) than I am currently, and generally enjoying the freedoms that came with said income — I find that living under the UK umbrella has made me feel like I could be poverty-stricken at any moment. That said, I love the culture and the way of life, so it was a worthy trade off, but that does not change the reality.

One thing that also sticks out, as was mentioned in that article, is the risk aversion that seems to be commonplace among all organisations this side of the world. In the US, companies are severely more risk tolerant (especially from an engineering perspective), and willing to push the boundaries of their current operations in order to achieve efficiency and modernisation improvements. The appetite in British organisations is largely to maintain the status quo, which inevitably leads to a full structural (and infrastructural) reorganisation as the “not broke, don’t fix it” mentality falls decades behind modern innovation. You can witness this reorganisation happening right now in the energy industry as DNO’s are shifting towards becoming DSO’s, slowly adopting technology and methodology that has been in place for 20 years in the US. It’s unfortunate, because from an engineering perspective, it feels like the organisation on this side of the world is either stagnating or completely overwhelmed by change, depending on which phase of technological adoption and requirement we currently sit in.