Linux has had support for not doing duplicate pages for a long time now. I am forgetting the name of the feature but essentially this duplication is a solved problem.

For different minor versions and builds of libraries?

This is basic paging and CoW (Copy on Write) behaviour. I agree, it's mostly a non-issue

That's only the case if the libraries loaded are identical, It won't work with slightly different versions of the same library (unless the differences are small and only replacements, so the pages remain aligned between different versions), and that case is very unlikely to be solvable

The parent comment doesn't talk about different versions and I wasn't either.