Who buys a PS3 in order to play PS2 games?
The people who own PS2 games most likely own PS2 systems already. Backwards compatibility sucks. I play all my PS1 games (like two of them) on a real PS1.
2 things.
-A lot of people will, because that allows them to only use one console for games from all 3. Less space used.
-At least in the US version, BC does not suck. They actually installed the Emotion Engine chip onto the board of the PS3. It has been said that the software solution for the EU systems will do the job fine. The reports that you are seeing are based on the 1.5 firmware, but the 1.6, that will be released on launch day, is what adds support for all of the BC-enabled titles.
Also, look at the difference in sheer numbers of titles supported in BC between the PS3 and the 360. The PS3, reported to support 1200+ initially, the 360 after being out for over a year, what, 250'ish titles.
When I worked at an EB years ago, and the SNES was coming out, 9 times out of 10, the first question asked was "will it play the games for the NES?"
We, as gamers may not care much about BC, but a LOT of parents and under-informed consider it a very big deal.