I had a friend in "support" who had build a lot of a data normalization system that I often worked with, and we talked about the phenomenon a couple times over lunch. Basically, she was a little offended about the lower pay and the "support" title, but would rather keep her work / life balance and relatively powerful position within the infrastructure stack, than join the production team for a raise. In hindsight, someone should have fought for the whole L2 support department to be better paid; there was certainly money for that (we were in a wildly profitable niche), and the support engineers had the high ground. But we were both young technical types, and didn't have the business / legal skills or the confidence to confront management.
I'm not sure how things have played out there in the years since I left, but if they wanted to, that entire L2 support team could take off and form a devops / analytics consulting firm, and probably multiply their incomes by some small integers. Then they could hire from the product team too, if they needed web/UI ;)