In a more general context (that is, without commenting on specific quoted posts) let me add to my original POV that Pelles-C is a very closed project in almost all aspects.
It relies on its own ide, its own libs, its own run-time, its own debugger, its own everything. This is quite understandable for an one man project, because it helps Pelle in having everything under control, and maintaining the project on his own. The AddIns are the only way provided for 3rd party support.
That was fine, as long as C was still fairly used for Win32 development, and as long there was not too much of a competition. Nowadays, things have changed drastically, as I have already presented in this topic. What Pelles C offers is no longer handy, trendy and/or unique. Being a very self-centric project does not really help in becoming more popular in todays standards.
For a moment (or more) lets forget about open source, cross-platform, etc. How about supporting project importing from other popular IDEs of today (e.g vs, code::blocks, dev-c++, netbeans, eclipse, the more the better). Or how about supporting popular CVS (git, mecrurial, etc)? Or how about a central place on the net for uploading/downloading installing/uninstalling AddIns from within the IDE? How about implementing stuff like
Dev-C++'s devpacksMost of these stuff are the norm nowadays in most (if not all) serious development environments. The IDE itself could also benefit from some improvements too (like enhancing the editing capabilities for example, or like being able to move/auto-show sidebars and panels).
All in all, I can think and I have presented lots (and heterogeneous) of reasons of why Pelles C is not popular. Some of those can be implemented externally, others require access to the source code. The main question is how and who will be convinced to invest its free time on such things, since they are already available in a plethora of Pelles C's alternatives.