I think financial institutions and governments maintain a reputation for being conservative institutions (in the general sense of "conservative", not in the politically-charged sense the word has today), so it took them longer to move to the more-prevalent corporate model of organization. As a publicly-traded company, Large Bank has to answer to shareholders just as much as Megamart Inc. and Acme Mfg. do so they have to keep up. And voters (many of them experienced in the corporate shuffle) have demanded that governments be more responsive, too. I certainly see that happening at the county at which DW works.
The thing about "niche talent" is that law and demand applies in spades: there aren't many jobs but the ones there are pay pretty well compared to more generic positions. An old friend of mine is a quality-assurance engineer in the medical sector. At this point in his career there are maybe two or three jobs in the region at his level. So it's hard to move about and he's spent more than a few months unemployed when companies left town, etc. When he's working, though, he's a very well compensated QA engineer.
And it does not help that, in hiring people, most organizations want someone who can hit the ground running, which calls for very specific skill sets. Even within broad categories of jobs, it's hard to avoid specialization. DSiL works in retail banking; it would not be easy for him to move to mortgage banking. A phone-app developer might be a whiz at C language but would flail around in the first few days of a job as a Swift developer unless (s)he got appropriate training. Sometimes the industry focus just isn't enough.