I remember when I used phpBB 2 a LOT years ago.. My experience was that requesting mod/ext was quick and people were lining up to help and create. This can not be said about the current version? What happened?! This mod is requested by a lot of people for several weeks, but still nothin'
There are many reasons why extensions are not being done as fast as you would like, not least that most of us also have a life outside of phpBB.
Another reason is that creating extensions is a new "learning curve" which takes time and couple that with the fact that some old "mods" just will not convert to extensions without the addition of events.
The writing of extensions is by no means a "closed shop" and you are more than welcome to create some.