Underpaid relative to other professions. Lawyers, accountants, doctors, MBAs, etc etc. Even civil servants once the final salary pensions are factored in. Low pay, low prestige (if that matters to you), low job security, relative to others at a similar level of education, responsibility, etc.
But that's true almost everywhere. In the U.S. it's true everywhere outside of the Bay Area, and perhaps Seattle.
I love Boston, for example, but the city is chock full of bankers, lawyers, management consultants, and doctors whose incomes often dwarf those of engineers. And they're much higher on the social ladder. You're priced out of the most desirable neighborhoods in the city, and if you're single, dating is tougher.
Obviously, it's not the end of the world. 99% of people don't make as much as investment bankers or white-shoe lawyers, and life goes on. But I think it explains in part why engineers are drawn to the Bay Area. The sky-high cost-of-living may make it a break-even proposition, but the bit of prestige engineers get there is a selling point.