I don't think so, somewhere else in this thread the developer of this job board says that his intention is to keep all listings forever, as this would prove that paid FOSS jobs exists in abundance. IMO a debatable approach.
I don't know what makes everyone so upset at old listings. They are listed chronologically, there is an RSS feed to follow for fresh things. It's not like it's thousands of mixed jobs where you have to hunt for the recent postings? I definitely don't object to someone adding an archive/expiry functionality that does not completely delete old job listings. If you look at the referenced ticket on github, I created it.
Keeping the old jobs as a separate search option (eg "[ ] include historic items") de-clutters the primary purpose of the site. That matters when you consider that few people enjoy the process of job hunting so will quickly abandon any platform with a poor signal to noise ratio.
I spend some of my free time to collect and post open source jobs someplace. That's my goal.
There's certainly analytical value in having every FOSS job you could have ever seen, but none for the end user.