You'll have to forgive me
But with all due respect, it's honestly quite painful seeing someone so uneducated about such a subject
Time to educate, as I understand not everyone knows such things
Incoming long paragraph
Computers/game consoles, are machines, the only difference is that the mechanical pieces are much smaller (microscopic actually)
It is for this reason that computers must be built on architectures, an architecture is just a name given to how the mechanical pieces are set up
Generally, PC's use the X86 architecture, Mobile devices use ARM, and in recent trends, game consoles use PowerPC
The PS2 uses an architecture called MIPS I believe.
Now, say you wanted to run a program made for a PowerPC machine, on an X86 machine, you'd need something to translate PowerPC code into X86 code, that's where emulation comes in, unfortunately, emulating the PS2 on Android is not that simple, and although I firmly believe modern devices are more than capable, we simply don't have recources to develope such a thing at the moment