Apple is ditching the word ‘Subscribe’ as a means to describe the act of telling your favourite podcast player to keep checking a particular feed and have the latest episode available at a moment’s notice. Instead it will use “Follow”, which seems to make a lot more sense as a way represent passively consuming a feed at no cost. Subscribe is one of those words that predates podcasts, I remember “subscribing” to newsgroups as a teenager and worrying that my parents were going to receive a bill for it. They never did.
My bet is the etymology comes from email mailing lists, where I think the word subscribe still makes sense. Funnily enough, in 2021 email mailing lists are having something of a renaissance. With paid newsletters being in, and advertising being out, I also expect this change will be because Apple will be pushing paid podcasts, where the word subscribe does make sense.