A lot of the people you list (and a lot more you don't, like BDFOY) are, frankly, getting older. Most of the people in that cohort are in their mid-40's to mid-50's. Many of them have moved out of positions where they do a lot of hacking on OSS. For example, many of them aren't individual contributors anymore. Many of them no longer work in Perl on a regular basis. This is just a normal evolution.
Pascal was once the shit, too.
My criteria for good software:
- Does it work?
- Can someone else come in, make a change, and be reasonably certain no bugs were introduced?