Because to me, an arcade machine is an arcade machine
I'm not sure how old you are, so I don't know if you grew up with the local arcades and spending hours and hours surrounded by the machines. I did, though, and having one of those in my house is cooler than any game system that has ever come out. Again, it's a highly personal thing for me. Take the hardware out of its wood or metal cabinet, and it loses something in my eyes. Sure it plays well, hell maybe even better with a CMVS on a TV, but to me it's just not the same experience and not what I'm after.