well its like when they were planning the xbox they were all.
'arr screw it, stick a 10gig hard drive in, a geforce 3 chipset, 64 meg ram, and a 700 mhz processor. oh and don't forget to stop the execution of unsigned code, job done!'
so you've essentially got a computer without the ability to do what you want on it, but luckily we've fixed that. so the xbox can play pretty much any media format, any game or application providing it has been compiled into an xbe properly and ported, and anything else you want.