Sony has a product for those who don't want to spend money to play games they already own and that's PS3.

Anyhow, why play PS3 games offline when you can instead stream them and lose progress if you get disconnected? That's clearly the superior option.

PS4 should be able to do last gen BC, as long as it is X360 games

Not really, what they (the XBox team) need to show MS is that they can make the XBox community grow, be it on PC or console.

OT: Isn´t PS Now supposed to be Sony´s solution for BC?

It would not be awesome if the PS4 had a PS3 emulator. For it to be awesome to the PS fanbase, it would have to be fully BC with all previous gens or be able to emulate games from the PS1, PS2 and PS3. I don't care about a PS3 emulator by itself. Sony doesn't need to or should add BC to the PS4. 

BC has been around a long time and because the xbox one is getting a very limited BC, it's a must have all of a sudden. Guess what, it's not. The wii u is BC with the wii but it's obviously not drawing people to buy the console. If MS really wanted to go that route, they should of designed their console with BC in mind instead of having a limited BC after the fact. Ultimately, it's just another feature that adds limited appeal to the xbox one. 

They will only do it if it makes them money so I guess discs are out of discussion for this. Whether they see a potential income which is higher than the costs of developing the emulator, we will see.

But yes, it should be quite easy in terms of performance.

Funny thing is, PS2 classics already where emulated on the PS3. There have even been some tricks and/or workarounds to get original discs working.
Though Sony had no interest to let people play their original games when they released PS2 classics.

A PS2 emulator shouldn't be such a big problem. Question will be, if Sony let's you play your original games then or if they only want to sell digital copies again.

As for 360 BC, MS simply has to do much more to sell their consoles. Otherwise they as well would only sell digital copies or have no BC at all.

If Playstation Now is the reason they aren't doing this then why are PS1 and PS2 games not on it?

They just need to update PS4 to accept the same PS1 and PS2 classics from the stores and the extra money will come rolling in.

With an understanding of the console architecture in question, it doesn't look so easy. The ps2 and ps1 should be penuts to emulate (it is on PCs weaker than the PS4) But while the Xbox One and the Xbox 360 both have architecture much like a PC, it's a different story over at Sony. I'll try to explain.

PS4 has very PC-esk architecture as well (Xbox One and PS4 are very similar in that respect) but the PS3 had a very irregular architecture called the Cell Microprocessor which splits its processing load across one main processing unit and six additional co-processing units.

PS3 was notably difficult to code for, because not only did you need to keep all six of these co-processors busy, you had to keep them precisely equally busy at all times, or the game's systems would fall apart. It was very fiddely.

Emulating the PS3 is extremely difficult because of this very esoteric processing setup. Without that architecture (which is very different to what the PS4 is packing) it needs to be run more or less entirely through software, and even computers superior to the current consoles aren't juiced up enough to be able to handled an entire last gen console running purely on a software level.

Long story short, I'd love to see the PS4 successfully emulate the PS3, but it's not at all likely. PS3's bizarre hardware design has shot Sony in the foot in that aspect. We're seeing early Xbox 360 emulation happening on PC, but we likely won't see successful PS3 emulation for a while. Although I do recall murmurs that somebody had managed to make one that could only play one game (I forget which) and reported that emulating a system for that one game took the same amount of work that it usually takes to emulate an entire console.

I can't explain beyond that point. I understand the architectures, but I have never contructed an emulator myself. But that's my understanding of the situation. Ask around, but the concensus is that that damn Cell Microprocessor is a massive road block.

From the tests I've seen they don't run great, especially AAA games, but it is in beta. I mean if you can link the ones that run on par that would be great.

Sony knows not many people want to play games without Trophies. Don't think they are in a rush to add it. It would be better to remake them with Trophies for PS4. My PS2 backlog is behind my PS3/360 backlog, because they don't give me e-penis points. I stopped playing Valkyria Chronicles because I heard it was getting a Trophy patch. So I waited and waited... and Sega failed me again. Now I lost interest and it too has been pushed to the end of the line, ahead of the games with no Achievements line. If Sega remakes this for PS4, I'll jizz. As for now, that game is behind 500+ games that I'm too lazy to play.