It's easy to blame (and in all fairness, many points are true), but I think a large proportion of coders just move on.
It's natural and it happens in every subject, in every context. When something is new, there is a huge enthusiasm to do new things. The PSP has pretty much had it's booming period - most things that needed to be done are done (to some extent).
Coders eventually get bored updating the same thing, constantly trying to achieve perfection. It becomes more of a chore than a passion.
At this point, it would be better for them to pass the project on to capable hands (if any) instead of walking away, as a new coder is not going to try and start from scratch on a similar app, as they would only get flamed "Why bother? XYZ has already done that".
People always want more, too. Thats the killer. A new piece of software is mentioned - people drool at the mouth at the thought of it. They wait, they get over-excited. Eventually they get it, and it's fun for a bit, then they want something new. Repeat indefinately.
Just accept that the scene will never be as booming. Some individuals will stick with it and continue to stay up-to-date and improve, others will not. No point worrying about the people who don't. Just feel lucky you have all the stuff you need as it is :¬)