Do you people really think that a giant of a company like Sony that is capable of making all these consoles and just about every other kind of electronic device that they make are not capable of emulating a console that they built? I believe that they just didn't care enough to emulate the PS2. Don't confuse not caring about the emulator portion of the console with not being able to do it.
Well, coders at Sony are humans too. They probably get paid a LOT for their programming. Yet during the transition from the hardware based emotion-engine emulation to pure software, they couldn't make a proper emulator for years. It had the exact similar bugs as the PCSX2 project like missing textures, games not booting, flickering screen issue in some games etc.. I can attest to that as I witnessed with my own eyes.
Sure, maybe they can in 'theory' make a perfect software emulator if they want to, if given enough time (say 3-4 years). I'm sure the team at pcsx2, if also paid over $5k per month and had 30-40 guys hired to do it, could achieve the same.
The difference is that anyone online has to guess at what they're doing, but the actual company has all the specs documented at their disposal to do it. It just does not make any sense to me to say that they are not capable of doing it faster and easier than anyone else, if they wanted to.