Distributing an OSS app requires neither a domain name nor an SSL certificate. And even if you shell out for these, they cost me vastly less than an Apple developer subscription. For somebody who develops OSS just for fun in their spare time, doesn’t make (nor expects to make) any money from it, and would rather spend time and other resources on interesting stuff, the 100 USD fee is essentially a no-go. I don’t mind paying for my hobby but (1) I’ve got more than one hobbies and I’m not rich, and (2) I’d like to perceive that the money I spend actually gives me something. For my purposes, an Apple developer subscription doesn’t feel like it is.