He's comparing KDE and Gnome core components (window management) and the linux kernel with developing iPhone apps. That's a bad comparaison in my opinion. Hacking on an operating system kernel or a window manager requires great skills that most kids (and adult devs) do not have.
A fair comparison would be iPhone apps Vs KDE or Gnome apps. And here KDE and Gnome get tons of new contributers each months, check how active is http://kde-apps.org for example, or the Ubuntu developer activities. Tasks that require less skills will always attract more developers or cooks or whatever in all professions.
Here's a Graph of KDE contributers http://dot.kde.org/2009/07/14/growth-metrics-kde-contributor... up to July 2009. As a KDE dev that follows the mailing list, I can tell you the list of contributers is still groing well. Not to mention all the people that build KDE apps without being official KDE devs.
A fair comparison would be iPhone apps Vs KDE or Gnome apps. And here KDE and Gnome get tons of new contributers each months, check how active is http://kde-apps.org for example, or the Ubuntu developer activities. Tasks that require less skills will always attract more developers or cooks or whatever in all professions.
Here's a Graph of KDE contributers http://dot.kde.org/2009/07/14/growth-metrics-kde-contributor... up to July 2009. As a KDE dev that follows the mailing list, I can tell you the list of contributers is still groing well. Not to mention all the people that build KDE apps without being official KDE devs.