Perl is still tremendously useful as system scripting language (one may prefer bash iif does not know Perl) and text processing. Perl was extended beyond its natural scope because in a certain time lapse, it was the only tool available to do quick prototyping and an aid to quickly deploy complex web applications (particularly).
Maybe its true that it has come to the final developement phase. Other languages, more focused on specific purposes and without the limitations/quirks of Perl (TMTOWTDI - There's more than one way to do it - is a problem more that an advantage), have picked up its most useful characteristics, so Perl is no more so central in application development and it will go back to its original scope.
If Perl will go extinct it would mean that other , better languages have took its place, but this is not a problem, it's normal evolution.