I've only been posting for a few years, but I have noticed a decrease in posts that were thoughtful, fact-laden conversations and an upswing in posts about stage dooring, if a seat location is good, and people asking for recommendations to show for a block of time 3 days later then the previous recommendation thread.
Perhaps people don't understand the site's search function, manually checking posts a page or two back, or doing an advanced google search. Maybe a sticky post with these directions would be helpful? As would a "recommend me a show!" sticky. It would keep those conversations contained and show past answers.
As for posting...I think life is simply happening for many posters--frequent and infrequent--right now. My love for theater is great and is a valued distraction from the world around us, but these days, there's more skimming of theater sites and more in depth focus on the things in news and the here and now. Add to that 3 job reassignments in 3 years and sometimes, I just can't keep up. My trips to the city from the Midwest have become more frequent, but they're now working trips where I research and collaborate with other educators, who, at the end if a long day are more interested in a nap then the latest Nottage play.