I have a feeling it's not so much hardware as software that retailers are on about. PSP is basically at about 1/2 the user base of the DS which is great, any developer could confidently make for that right? Obviously not, for developers hardware sales only matter so much if the software doesn't move. system month monthly sales cumulative sales PSP Feb 07 1,023,000 29,861,000 DS Feb 07 1,974,250 42,076,000 a little more then 12,000,000 units of software moved by DS over PSP in America system week weekly sales cumulative PSP 03/11/07 109,750 10,853,750 DS 03/11/07 789,250 61,522,000 just under 51,000,000 more units of software moved by DS over PSP in Japan for Europe.. I don't know sorry. in any event given these numbers if I was a developer I'd make 5 games for the DS and put 1 or 2 on the PSP and cross my fingers. As far as hardware the difference is 18,000,000 or so in DS's favor as far as software... it's probably closer to 55,000,000 - 70,000,000 in DS's favor..
Essay Pro