I'm guessing the majority of people now in their 50s and 60s in computer-related careers had very eclectic jobs before settling down in computer-related stuff. After all, many never used computers at all until college or beyond.
Edit: my point was not that specialized software applications didn’t exist. It was that people were expected to be able to jump from stack to stack when they change roles in a way that has disappeared from modern job applications.
Well, and mainframes. And trading and financial systems. And numerical/scientific computing. And network services. And web sites and e-commerce. And flash, java applets, and browser plugins. And control systems. And operating systems and tooling. And cell phone applications. And games. And video/image/audio/music processing. etc etc
Oh, wait... maybe not!
That’s the point I was trying to make. Not that the software didn’t exist or people weren’t doing specialized applications.
Depending on what you could bring attention to in your prior experience and the size/needs of the new orgs you seeking to move to, certain transitions were more feasible than others, but you could easily spend decades working in mind-numbing enterprise applications while wishing for opportunities in game development or trading or whatever and never get your resume so much as looked at. (And vice versa, even, for those who dreamed to "retire" into the supposed quiet of enterprise apps or government IT or whatever)