It was clearly the pricepoint and the selection of games on offer. Look at the ps1/ps2 launch game titles and they were much more compelling than the initial titles on offer on the ps3.
I dont think (as some do) that consumers failed sony. Consumers will always buy what interests them and sony had to give them something they wanted. The ps3 initially had a lot of problems and the price was too high. Also the initial problems with backwards compatibility and the lack of it in the slim skus means that people who love their ps2 games have been unwilling to switch to ps3 cos they wont be able to play it - which is why the ps2 still so very popular (>1million sales this year).
However, i dont think sony failed their fans. In their efforts to make up, they have delivered some great IPs this gen and i dont think anyone can doubt the value of the ps3.
<a href="https://psnprofiles.com/fauzman"><img src="https://card.psnprofiles.com/2/fauzman.png" border="0"></a>
