Degital Foundry has said that native backward compatibility is on the way for the PlayStation 4. They are not speaking of the PlayStation Now service, but full emulation on the PS4 console. They are said to be working on HD visuals for the older games. Sony is “actively pursuing the ability for older titles to run without the blurry upscaling seen on PS3, suggesting that native HD resolutions are being targeted.”
The PlayStation 2 is Sony’s biggest console; it made Sony the gaming company that it is today, numbers wise it is the most popular games console in history. Sony is sitting on a goldmine of legacy with its PS2 library, most of which has already been remastered and reissued. It’s probably too much to ask the company to figure out how to slip in the trophy system somehow, but HD-upscaled versions of the games will definitely appeal to gamers who like the PS1 and PS2 gaming libraries.