> But after the pandemic, the release schedules slowed dramatically to once every 3 years, and the new features weren’t really groundbreaking, not requiring deep education to keep up.

This really seems to be the clincher here -- COVID surely contributed, but "post"-COVID if there's not much to talk about, why make the trip?

I'd be curious to hear how often newbies showed up to these SQL events pre-COVID. Was there interest from people outside the regulars? Were people truly excited to learn about SQL technologies?