Three reasons:
1) The DBP Showcase hasn't been updated for ages (and won't be until the new site goes live), all the DBP games have to be found in the newsletters and forum. While there are plenty of them, there are not as many as BB have. You could you say this is because ....
2) ... the 'average' BB user is both more experienced and typically an older age. This means they actually get stuff finished. The percentage of people here who *finish* something is very small indeed. This could in turn be blamed on ...
3) ... DBPro taking longer than BB to become anything resembling 'stable'. While people here were battling with the < v5 upgrades, the BB people were churning out game after game. What we've seen in the past couple of years shows that DBP is now certainly capable, and there are some extraordinary games out there made with it, but the delay at the start combined with point 2 above means they'll probably always have the 'lead'. I'm not sure this actually matters in the grand scheme of things, and while their showcase is visually very impressive, if you actually start downloading and playing the games the quality is quite proportional to DBP titles.
Too much, too soon, too far to go, too late to play
The game is over, the game is over
