I wouldn't say that FastCGI is dead. Stable, yes. Dead, no. It's been working beautifully on my Debian boxes for years, and is still supported in the new Sarge that was just released. I believe the burgeoning Ruby on Rails community is picking it up, too, as one of the persistent mechanisms of choice. It just works, and darn well I might add.
One particularly thorny problem it helped me solve recently- I provide "boutique" hosting services for a rather large perl-based CMS that's under heavy development. I have clients that are on the stable branch and are happy where they are at, and clients that want to run the development "bleeding edge" branch. mod_perl makes this difficult because of namespace clashes, while with FastCGI I can run multiple long-running "instance scripts" and everything just works. And nicely, too.
You do lose the direct integration with the Apache API (I love mod_perl), but FastCGI is a very nice alternative persistent environment that's language independent.
-Any sufficiently advanced technology is indistinguishable from doubletalk.
Perhaps that just means that they have both already reached perfection ;)
Seriously though, FastCGI is a very mature technology, so I can understand why development may have stopped. After all, when was the last time Apache made any changes to the way CGI works?
As for PersistentPerl, there is only one registered bug with the project on RT, and it is platform dependant (OSX), and includes a proposed fix.
Really, there are lots of perl modules that haven't had an upgrade in ages that are still relevant. How long did Apache::Session go without an update? HTML::Template has only had one release in the last 3 years and it is still very heavily used. I'm sure there are many others...