In my opinion, it's perfectly reasonable to ask if a project is still being maintained. I often come across packages that have had no updates in a year, and it's hard to know if that's because they aren't being maintained, or if they are being maintained and no updates have been required.
I hear the argument from some open-source maintainers that they have no obligations to the people who use (and depend on) their software. But there are lots of open-source developers that actually want people to use (and to depend) on their software. Being an open-source developer of a widely-used application or package can bring great benefits to the developer - at the very least it garners them respect from the community and potentially from future employers, and in some cases it can lead to huge financial rewards: acquisitions, great career prospects, paid trips around the world to speak at conferences, etc.
It's definitely more of a two-way street than some developers would lead you to believe.