Not sure this is a very realistic scenario. Web design, as a career, isn't exactly old enough that there is a large demographic of people who are on their way out to retirement and, as such, have simply stopped evolving their understanding. What we do have are web designers who didn't quite get the memo that they have a career which is constantly evolving, and that if they wish to remain competitive they need to keep learning. They're on the way out because they won't compete.
Flash is still very important for certain websites. Very nice for, say, a car website—or a movie website. Due to the lack of a proper development environment and backward support it is prohibitavely expensive in many cases to do something like, say, a game in 'HTML5' (which is so the wrong name for this, but people use it anyway). It can be useful for some select scenarios in video, but that's on the way out. Alternative open standards are on their way to replace many of these things, though.
A designer/developer who is using Flash in other cases is just a crappy designer/developer. That's really all there is to it.
