And just imagine how difficult it would be to emulate all that fancy hardware. Despite the fact that the PS2 relies heavily upon the proprietary Emotion Engine chip, an emulator would be a beast to code.
I don't think any single processor CPU (unless you get like a 10/20GHz system, mind you) would be able to reasonably emulate a PS2... if I'm not misaken, the PS2 has 5 independent processors (graphics, sound, etc etc), so to emulate all that on a *single* PC processor.... ouch.
Okay here is what I think.The reason due to which the development of psone emu took time is because,the research on these emus started from zero.I mean that there was not concept of psxemulation.But now we have great emu authors who know quite much about emulation.So I think that the emulation of PS2 will not be that difficult for them.
i have known about mame since 1996 and at that time it ran quite a lot of games perfectly and i think it was in the twenties and now its in the upper thirties or so. i would say mame is about 8 years old or so (just guessing but dont want to research to find out for sure)
so they had a pretty good grasp on how to emulate back then too
and it still took a long time before psx emulation caught up to arcade emulation