Speaking from experience, I think many people (many youngsters/newcomers especially) being too optimistic about emulation potential and it's evolution. Not saying you are in these categories rackoon, but although it's possible to emulate 6th-gen consoles and arcade hardware, it's still way too early. MAME development has been a 13-year process that has been slow and emulation in general for our needs has taken about 10 years to get to the comfortable point we are at now. As consoles from 5th gen onwards started to catch up with arcade and eventually PC capabilities, next-level emulation will develop much slower.
I also frequently remind people that arcade cabinets are not really a suitable environment for the library of games on these platforms due to the increase in joypad/control complexity, so question whether the demand for this level of emulation will really be high enough to progress emulation maturity, as ultimately that generation of games were not borne out of the arcade action demand earlier consoles were. I've got all I could wish to add to my cabinet by now and I'm sure many feel the same. Whilst it would be an achievement, this generation of games is best played from your settee with a joypad, in front of a big-ass TV.