Yes, a PS3 emulator does exist.
Yes, a PS3 emulator does exist.
You're asking about how long it might take to handle a decent number of games, and whether the host system needs to be significantly more powerful. It sounds like you're concerned about performance and resource requirements.
It really comes down to the capabilities of the developers. If they achieve a major advancement in emulation, we might see improved game support within the next few years. Otherwise, it could take a long time—possibly indefinitely. I’m not sure what power requirements are needed for emulation, but it seems to depend on how well the emulator runs the system. Just like games, emulators must get better over time. Dolphin is a good case in point; a few years ago it was hard to play many titles, but now they work smoothly on similar hardware. So the timeline really varies between emulators and the teams creating them. I don’t think Xenia or RPCS3 will be practical for another 4 to 5 years.