I'm reasonably certain that I am about as old if not slightly older than the invention of in-ear headphones. I'm also reasonably certain that I have always used "headphones" to refer to any small portable speaker designed to inject sound directly into the ears. I'm absolutely certain I have never used the term "earphones", although "ear buds" was/is a common synonym for in-ear headphones.
I’m probably around 2 decades older than the invention of earphones and people definitely did used to call them that here in the UK.
Then the US English is winning out because we never said earphones over here. I’m much older so have a clear memory of when they hit the market. We said earbud for a while but that was a momentary distinction and it seems we’ve mostly reverted to our generic term of headphones (which lacks any distinction on form factor ) so we use it for pretty much any and all cases.
I actually think the AirPods naming helped this as it’s kind of a clunky product name that’s nearly a misnomer if you consider iPod is still a part of our vernacular. I don’t hear people saying “where are my AirPods?” Instead it’s “where are my headphones?” Had it been called AirBuds then maybe it would have stuck since ear buds was a thing.
As I think back, I feel like earbud is distinctly tied to the corded iPod accessory. As that died out, so has the term.
You are... 150 years old?
https://patents.google.com/patent/US454138A/en
This nipple is adapted for insertion into the ear, and is ordinarily covered with a rubber cover to lessen the friction against the orifice of the ear.