If the vendor wants to ship application libraries on a per-release basis, that only affect their workloads, but if they start shipping system libraries, they recreate one of the problems that Unix has avoided and impose it on the whole community.
Shipping modified system libraries may not cause the end-user "DLL hell", but they will cause the application authors to be out of sync with the core developers, and also out of sync with every other application vendor, whether or not they use standard or their own hacked libraries.
That won't scale. It sounds like it's Order 2^n with the the number of versions outstanding
That in turn means that each additional application vendor who does this makes the situation worse for everyone, by increasing n and therefor doubling the work for the community.