My hypothesis is that, given a large enough team or organization, a large enough number of projects, and a large enough number of dependencies, there may be some benefit in having somebody who specializes in keeping (3rd-party) dependencies up-to-date, in terms of economy of scale and correctness in applying updates.
If you have 10 projects that use the same dependency (let's say django-rest-framework), would it be better to have one person who spends time really grokking the release notes and adapting the codebase for breaking changes? If you know how to update django-rest-framework for one project, you probably know how to do it for another project, right?
I have usually picked up the upgrade and other sucky work for the teams I've been on. It's a thankless job and they rate you low for not delivering business value. Same with the security work I do. You end up as a generalist, and most places only value specialists.