De Icaza's Mono and Moonlight projects have been extremely divisive, splitting the free and open source community many ways. After Novell was bought by Attachmate and taken private last year, Mono was jettisoned by the company.
KDE had one disadvantage from the beginning - it was an European project. It had rather simple aims - to clone every function which was available to Windows users so Linux users would have all that functionality at their disposal. It has done much more than this and today is eminently more usable than GNOME. KDE never bothered much about marketing itself, the team simply produced software which was good.
GNOME was always viewed as an American initiative. There was more marketing, more buzz words (a trait that continues even today) and many structures of so-called leadership. Until at least release 2.0, GNOME was a clunky, heavy desktop, which was buggy in the extreme, Ximian was something of a nightmare; I personally had to reinstall Linux twice during the time when I was experimenting with it after Ximian installs went terribly wrong.
GNOME 3.0, released last year, hasn't set the Thames on fire either. It has resulted in a litany of complaints.
It is thus surprising to find De Icaza, who has caused a considerable degree of division in the free and open source software community and among Linux desktop developers, not telling the full story when asked why the Linux desktop has not gained more traction.