Maybe someone has a router down there

It's like calling all fuel diesel.

I think they specifically mean Wi-Fi, not confusing it with cellular.

I would be surprised too if I went into a cave and suddenly my phone is connected to Wi-Fi. Where are the access points? Who is running internet all the way out here? I don’t see any telco boxes or signs of a human presence. Why do the speeds get faster the farther I go? Why did my phone connect to some random network when I specifically told it not to do that? It would be even weirder if it’s WPA3 protected or something because I obviously don’t have the password for the cave Wi-Fi

I'd say these examples are different, more like Kleenex where brand names become the common term. This is more like when parents used to buy a Wii game for your "playbox station".

I know people who don't know what an Ethernet cable is.

Internet = wifi / mobile data. And that's it as far as they are concerned

Routers, modems, switches, bandwidth, Ethernet etc. That's all just mysterious mumbo jumbo nerd shit. They only know that wifi = the symbol on their phone and that it makes their apps load. It's crazy.

Also "10G" as a shorthand for DOCSIS 4.0.

There is a term, that I am too lazy to search, that when a brand or technology is so widespread or used, that the name of the brand or technology becomes the word used to describe anything that ressemble that brand or technology.

Wi-Fi and iPads are definitely some of those.