I've read some stuff about it, and from what I can gather, it's too difficult for them to do backwards compatibility via software, so they have to do it by hardware.
The old fat launch ps3s had backwards compatibility, and to do that they had to include extra hardware inside the actual machine (the emotion engine).
I know with my ps3, I only played a select few ps2 games on it, and I still have my ps2 if I ever want to go back to it.
Backwards compatibility sounds great right at the launch of a new console, but IMO, it's really not that big of a deal once a few proper AAA titles have come out.
I'd rather have a cheaper new console (the ps3 launched at $1,000 here, the ps4 is launching at $550), than the exact same console for $1-200 more that can also do what my current ps3 already does great.
That is the argument against BC. "I don't want it, and don't want to pay for it". A reasonable argument.
However the Playstation in particular has been BC since the PS2. The PS2 was 99.99% BC out of the box. Not just for the launch window, but for the hundreds of great PS1 games.
Obviously then the PS2 library exploded and is quite possibly the greatest console of all time in terms of sheer number of quality games released on it.
When the PS3 was being teased, Backwards Compat was not only announced, it was further declared that all PS platforms would be BC forever! Remember the PS9 commercials? Same timeframe.
Then the PS3 launched, had no good games, zero. One of the worst launch line-ups in the history of big console launches. Backwards Compat was a huge selling point for me. And I would assume this was a huge selling point for others with hundreds of quality PS titles on the shelf.
The other argument is "if you want to play PS2 games, play them on a PS2".
That argument doesnt work since hardware fails. When PS2s stop working, that's it. Your games are done, worthless, unplayable.
And of course there was the BIG selling point of wireless controllers and virtual memory cards, major convenience factors for the PS2 games on the PS3.
HD remasters were the compromise, and some of them are excellent. But the sad reality is only 1% or less of PS2 games got HD remasters, yet there are another 100+ games worthy of the treatment.
PS3s are less reliable than the PS2 in terms of hardware, most will fail and then not only will the PS3 games be worthless coasters, the PS2 HD remasters and all DLC will be worthless bits of memory, unplayable junk.
Meanwhile I can fire up a perfectly working, (and actually improved with some user mods) Baldur's Gate game on my Windows Vista machine despite the fact that BG was developed before Windows vista existed. Magically it works, and my PC was not any more expensive.
I agree that the more great games that come out on a system, the less likely most are to play old games. But some of the best games ever made are old, and will always need to be played! I had to get some janky Component Out to HDMI converter to even use my PS2s... and I forgot how annoying the short cords are, and the physical memory cards.
I used to have a BC PS3 but it died within 1 year like most early PS3s did. But I was like 90% PS2 and PS1 games on it before it died. But I've played old PS2 and PS1 games as recently as a month ago, just like I play some old PC games sometimes too.
The difference is with the PS4 and XBONE, there is no way to play "old" games that came out a month or 2 ago, can't even play PSN content on it.
Even if you combined the entire library of both consoles, neither have a game on it right now that is even very good, or AAA. You can't play GTAv on it, or GTAIV or GTASA etc...
I can NOT WAIT for thief. Ohhhh boy been so long, too long only 2 months left.
