It may sound strange, but, they sold the console with huge losses at the start and still selling like this. And the ratio of software/acessories haven't make up this loss yet, if ever will, and if they sold more consoles the losses would be even higher and with the same ratio of software/acessories the things would be much worse.
So, PS3 had to be in the last position for many time, til they could sell the console with at least less loss and then make a come back.