It is because of Adobe AIR.Which is a cross platform runtime. Contrary to popular public opinion, Flash and Flex is actually a stunningly beautiful platform to code in. It's a very very mature platform, with an excellent community, and amazing libraries. (As a matter of fact, the creator of Angular JS wrote a blog post citing some of Flex's features as his inspiration). It's just that Adobe keeps screwing up their Runtimes. Flash and AIR both have performance issues which is why they are starting to get left behind now. For enterprise softwares,its cheaper and more optimal to have a single codebase that can work across platforms and in return take a slight hit on the performance.

I agree flash/flex is a great platform to develop on. From the language, to the IDE, to the API. It's like a strongly typed javascript with XAML done right. You can create a great looking app that shares the same code base between the web, iPhone and Android.

I've done some ActionScript freelancing back in the days. The demand for ActionScript programmers is actually rising, because everyone moved away from the Flash platform, but someone must maintain the legacy code and do the jobs Flash is best suited for.

1. Web and mobile games.I see Adobe Air is getting popular as a cross platform game dev library + starling , feathers , etc ... 2. Flex dashboards and reports in banks( e.g.Morgan Stanley ).

Probably for rich reporting tools in flex.