> ...or outright banning prebuilt binaries (the Gentoo and buildroot way).

You, uh, haven't used Gentoo in like twenty years, have you? You've been able to host your own prebuilt binaries (or use the prebuilts of others who bothered sharing them) for as long as I can remember (FWIW, I started using Gentoo in 2002 or 2004). The Gentoo folks decided to set up official binary package servers at the end of 2023 (look at the Dec 29, 2023 news item on the Gentoo home page for more info).