Over the last couple of months I've been watching people on the subway trains to and from work, I've noticed a much higher number of people playing PSPs to people playing DSs.
The ratio so far has been about 5:1
Obviously the numbers of DS sales can't be lying and I have no reason to doubt they arnt true, Even sony knew going in that Nintendo was a hard opponent in the handheld market even if they couldn't hold second place in the console market, which is why they added the extra features like movies, music and internet to sweeten the deal. Many people are simply finding more use for their PSPs in public than their DSs.
This isnt to say there arnt good games on the DS. They're just DIFFERENT for the most part, Funny stuff, maze/puzzle arcade action games, all better suited for playing and shutting off halfway through even if you havent saved, where as PSP games are designed to be more time intensive, RPGs, long adventure games, 3-5 minute long race tracks things you wouldnt want to loose your prgress in... true it's not mutially exclusive to either system that they have these types of games, heck half of my games on PSP I can quit out of without feeling a sense of loss like Ultimate Block Party or Lumines, while there are a few PSP games that are long and involved like Phoenix Wright or Trace Memory and even ports of other games like Need For Speed and Burnout Legends.
Nintendo's policy has always been to keep gaming open to younger individuals because they're the people who become the 20 and 30 somethings that still play games today but this means they get a bad rap for being childish. Dig Dug and Mr Driller games, Zookeeper they all look very colorfull and candy like and while games like this and a half dozen Dora the Explorer and SpongeBob games make up a lot of their catalog it's not all they have, they're just the most visible and it makes people who enjoy the occasional bloody actionfest feel like they're being talked down to (remember Nintendo was the company that said you didn't need blood and gore in Mortal Kombat or thought beating up chain wielding street walkers in Final Fight was unacceptable) so their insistance on feeding the younger players need for games just hurts their reputation further and the people defending it take offense to the word childish even though that's really the most simple term to discribe their games (ie. Childish - posessing a childlike or youthful point of view.)
Meanwhile Sony gets a bad rap for looking like al they care about is sex and violence, this is also an over generalization, or we probably would never have played Katamari Damashi outside of a japanese import. What makes that anymore "childish" (for lack of a better word) looking than a mario game? Nothing I can spot. But they continue to gain the 20 something dollar because they have lots of sexy CG characters Running, flipping, kicking, shooting, killing etc and sony knows this is what they want to see. Meanwhile noe one ever notices the pile of Spongebob games in the back with the PS2 logo on them because even the stores know they arnt going to sell as fast as they would on one of Nintendo's platforms for the very reason I detailed in the last paragraph.
But maybe I've over thought it and it's simply that people prefer to be seen with the "sexy black adult device" the PSP looks like rather than the "colorful toy" that the DS comes across as when you see both of them from a distance. I know I'm personally waiting for a Black DS to be relesed before I buy one, and I totally expect to or I wouldnt already have bought games for it in anticipation of that day. With the PSP, Sony went for the high price point iPod/cell phone crowd rather than gamers (which they were going to get anyway, the PS2 made that evident) because they knew they could get them they've always been about form and estetics for their devices being seen in the street, Nintendo on the other hand is usually about function except when they pulled out the GBA micro which many concider a horribly failed attempt and grabbing the same type of person, but for nintendo it dosent matter because people will always come to their system for fun simple kid friendly games and a lower price point because that's what they'll always generally be known for and maybe something a little extra long the way. There's enough for both hardcore and casual gamers on both systems, but Sony is a Media company and they know they can get more movies to sell faster on thier underdog than games in the first couple of years which is why the catalog is slightly weaker in comparison. People wanting a wide varaiety of games will see the 4 dozen on the shelf for the DS and the lower price tag and go for that and that also translates into better sales.