Either I'm misunderstanding or this is a non-problem. You can specify older versions of a package when you install it. You can also manage them with packrat. As long as researchers share their language and package versions, you can fully reproduce their environment. (And the base language is really stable, almost to a fault.)

This is just a bad way for the author to promote their own library for dealing with this. The way their library seems to approach this (using dates instead of versions) seems horrible too - on any given date I can have a random selection of packages in my environment, some of them up-to-date, some of them not. So unless all researchers start using the author's library (and update to the latest versions of everything just before they publish), it's only making things worse and not really solving the problem it claims to solve.