Scope creep destroys projects and software. Most software is bad because it does too much, so most of it barely works and of the parts that do kind of work, they don't work together.

Writing code is easy. Not writing code is much harder. Know what code to write, and what not to, is hardest.

The "willing to maintain your work" forever is the crux here - the open-source contributor is doing some amount of work to bring their contribution in line with the expectations of the repository, but it's up to the repository's maintainers to decide if they want to take on the work of maintaining that contribution forever. And that asymmetry exactly what TFA is about.

If there's great features missing form a library which are out of scope for the library, you have options - fork it, make a new library depending on the other one, launch a new linux distribution, and so on. These options require taking on the long-term work that the other library is saying (implicitly) that they don't want to do.

Libraries /should/ be tightly scoped and think hard about serving broad use-cases with simple API's: Otherwise maintenance, documentation, and discoverability of features become nightmares. It's also completely OK for composition to happen, as new libraries serve new sets of features for their own specific use cases, with dependencies on existing work. It's an ecosystem! It's ok!