I don’t know if this is really a “so broken” instance. /bin and /usr/bin (or sbin) have never been well separated, to the point where many distributions just symlink to /usr anyway. If you don’t want an initramfs to provide binaries you need them somewhere accessible.
They were defined sure, but without distribution adherence they weren’t actually, this has been the case for a long time. Out of all the distributions, Gentoo is probably one of the most sensitive to this issue since most others have used initramfs or initrd for decades and Gentoo has always made it optional.
If the post was about FHS adherence I’d agree more.
of course not, any program that has it own install script install it on /bin because it's easier, and why need that in a early boot, what's the difference, was always a workaround, wasn't needed to complement anything before, and don't need anything now