If all PS3's can run PS1 games then they can run PS2 games anyway. There is no excuse from Sony to allow backwards compatibility for one systems games and not the other.
AS MENTIONED BEFORE - COST AND SONY CAN DO WHAT THEY WANT
Maybe if they just left the PS2 Backwards Compatability alone and not removed it or had emulation it would put an end to all the people complaining about it on youtube and across various websites. The threads and videos are out there for anyone to see it is a big issue.
ITS NOT A BIG ISSUE - ONLY AN ISSUE FOR THE MINORITY (A VERY SMALL MINORITY
If the Playstation 4 doesn't have full Backwards compatibility for all previous Playstation titles from all Playstation brands i wont be buying one as all i would really be doing is buying a system with limitations as to what Playstation games i can play on it.
WHY SHOULD IT. I WOULDNT MIND PS3 BC BUT NOT THE OTHERS. EVEN IF IT DIDNT I WOULDNT REALLY CARE AS I'LL BE BUYING ONE FOR THE NEXT GEN OF GAMES
I'M SORRY BUT I HAVE NO IDEA WHO WOULD BUY A PS4 TO PLAY PS1 or 2 GAMES. THEY WOULD BE STARK RAVING MAD TO WASTE THERE MONEY ON THAT.
The Playstation 2 has full backwards compatibility and cost a bomb for Sony to make and they never removed any of the BC features on the PS2. Yes the Ps2 was expensive on release but did that stop people buying it, No it outsold every competition thrown at it. Sony's best days was with the Playstation 2. That system had sequals to previous Playstation brand Games many that where bought with the Playstation 2 at the time. We saw a new Broken Sword,Music, Resident Evil Outbreak, New Exclusive Grand Theft Autos, and plenty of many to numerous to list other great sequels like Call Of Duty for Example. Plenty of exclusive sequals on the PS2 for that game but yet the PS3 hasnt got exclusive Call Of Duty titles.
Look at the current sequels line up for the PS3 its mainly sequels to the following , Encharted,Resistance,Killzone, Little Big Planet
When did you ever see any new titles from a popular PS2 game like Music 3000 or any new music game for that matter on the PS3. See my point now.