Seigo: on introducing new ideas to free software communities

This is only partially true.

While users of course do not care about libraries themselves, they care a lot about what applications developers can deliver given those libraries.

This is especially true for applications created by KDE developers because of KDE's wide range of libraries which provide a significant part of what users perceive to be application features.

Improvements in libraries can both yield direct improvements in applications and free up application developer resources for domain specific work. Both things that users care about, independent of whether they are about libraries as program building blocks themselves.