Our AC unit in our condo will have been humming along service free (knock on steel and iron) for 50 years next year. I’ve a feeling a lot of the older stuff got switched out for efficiency or looks. Most old refridgerators that got landfilled in the 40’s-70’s went in still running. We have one up at the cabin in virginia that still runs, on gas/propane, and you have to turn it upside down every few years...
we've had one window air-conditioner in our pretty big house and it does the job very very well...