Pinning, escrowing, and trailing all help, but I'm not sure "this step will be eliminated" is inevitable.

Package manager ecosystems are highly centralized. npm.org could require MFA (or rate limit, or email verification, or whatever) and most packagers would gripe but go along with this. A minority would look for npm competitors that didn't have this requirement, and another minority would hack/automate MFA and remove the added security, but the majority of folks would benefit from a centralized requirement of this sort.

Yeah, I am looking at that on the use end. It sounds like on the python side this type of thing will be more standard (uv now and soon pip supported with version date requirements). I think time is a big missing element in many security in depth decisions. It can be time until you adopt like use no package newer than xx days or time it takes to deploy etc etc. Unfortunately the ecosystem is getting really diverse and that means ever more sophisticated attacks so we may need to do things that are annoying just to survive.

Why not just release escrow? If I try to push a new release version another developer or developers have to agree to that release. In larger projects you would expect the release to be coordinated or scheduled anyways. Effectively we're just moving "version pinning" or "version delay" one layer up the release chain.