So they are
Lets see, I've got a c64 emulator, an Amiga emulator, a Glide (old 3dfx driver) emulator, Dosbox, a BBC model B emulator, a ZX Spectrum 48k emulator, I even think I saw some console emulators on the net a while back that I for a short time considered getting, but truth be told, I haven't found a console exclusive game yet that I wanted it badly enough. It doesn't automatically mean that I won't ever get one, but so far, I don't see the need for one, real or emulator.
My computer is so horribly that it can't run console emulators for anything newer than the SNES and even some of those are iffy. The controls in Axelay aren't quite as smooth as they were on my SNES before the game stopped loading.