You think of distribution packaged rpms/deb, but the softwate developer can self publish, and you'll see plenty of self published packages in ppa, copr, flathub, and even just loose websites because it's not rocket science to make an apt or yum repository. However the distribution versions may take a little more time, but more likely to work together as a cooperative whole. Flathub has a decent shot by allowing concurrent versions of dependencies to install, while preserving the concept of updating dependencies independent of the package maintainers.

However, as you go down his chart, it's less likely that you'll reasonably update after install. You may get the latest at the second you install, but 6 months later you'll likely be stale. You may neglect to update npm in each and every project, or it may automatically dependency lock (because self publish nature results in developers having to vet dependency updates, and devs are lazy about that).

I assume he refers to npm/pip/cargo to be the multiple os option, not saying the last one is obviously better for multiple os. At least that has to be because that's the only option that is os independent.

Of course it sucks because the essentially uncurated dependency trees result in either instability on updates, or missing updates. Of course also the natural OS updater won't help you out with pip/cargo/npm, but it will help with apt, yum, snap, and flatpak.

I was talking about the other ones, but since you mention it, yeah, many people use Bash on Windows, from Git Bash which is part of Git on Windows, which pretty much any developer forced to use Windows will install in order to use Git.
Developers often prefer to have less interfaces to maintain when possible.