The Pan project is nothing if not resilient over the long term, not unlike desert-dwelling toads who bury themselves in mud and lie dormant for months or years, awaiting rainfall to make temporary ponds and trigger frenetic activity to ensure future generations will survive ;-)
Currently Pan is without an active lead developer, but is still being shepherded and released with new patches by Petr Kovar, who might as well be designated as the project maintainer. Petr is the one who contacts the package maintainers of the various distros, ensuring they have the latest working source code, and handling what passes for the project's Public Relations. This is a non-trivial amount of work and essentially thankless, and if you use Pan you should take note and appreciate his efforts.
Unfortunately we appear to have lost the individual embodying our Institutional Memory, Duncan. His last posts are from 2018 and, given his devotion to Pan over so many years and his somewhat loquacious (I should talk! Glass houses, etc.) posts to help users, I don't find it credible that he simply lost interest. I suspect, without any evidence save his absence, that Duncan has gone on to that Great Newsgroup In The Sky.
When Charles Kerr came into the project, he completely rewrote the original Pan newsreader, which by that time had become somewhat obsolete and 'piles of code' afflicted. I believe the last release of the 'old Pan' was 0.14.2.91 - "As She Crawled Across the Table' in January 2004. One thing I liked about Charles was that he kept the eclectic literary release names, a practice that has survived even now ;-) Eventually Charles grew bored with the Pan project, as it was operating smoothly and presented few challenges for him. He went on to rewrite the Transmission BitTorrent client, and still contributes there from time to time.
During the long subsequent lead dev drought, Kenneth Haley contributed patches and features, but was not interested in becoming the 'Official' lead dev for the project.
Heinrich Müller came along after a year or two and became the most enthusiastic and effective lead dev since Charles. He not only resolved many long-open issues, but added features -- some of which had been requested for years and years -- and basically bootstrapped Pan into viability once again. Heinrich basically saved the project in my opinion. He has since moved on, and Pan is once again in one of its 'dev drought' cycles, but in the interim there have been numerous patches contributed by users who are also coders, and these have been merged into the source by Petr Kovar to make releases, such as the most recent 1.46 'Hic habitat felicitas'.
Many open source projects are created, thrive for a time, and then settle like silt to the seafloor, unloved and abandoned. Pan has so far avoided this fate, by virtue of periodic rescue by developers who find it interesting enough to embrace and improve. The core of longterm users, many of whom subscribe to these mailing lists, also keep the project alive and contribute such improvements as they can. I don't see any reason why Pan cannot continue to be a viable project for as long as Usenet continues to exist.