Even in my limited experience, I have seen big, well-funded software teams in companies doing retail, manufacturing, transportation, shipping, food service, etc. Those developers do not typically make SV wages (and generally have better work-life balance), but they do frequently earn comparably to lawyers in their cities.
An example in the insurance industry from Dallas, a city not known for being a tech hub: https://stackoverflow.com/jobs/417604/mid-senior-level-net-d...
Or telecom in Atlanta: https://stackoverflow.com/jobs/392595/senior-software-engine...
It might be fair to say these industries have more leverage in the US because they can serve a bigger market. But it's not all about the types of products they make, there are definitely bigger issues that drive the comp differential. I would love to learn more.