Assuming the presentations are equally high quality (in terms of communicating ideas) and the presenters are equally expert (in terms of the ideas themselves).

Assuming the presentations are equally high quality (in terms of communicating ideas) and the presenters are equally expert (in terms of the ideas themselves). That's certainly not always true. But my sense is that the era of strong and plentiful tech meetups is a thing of the past as well. While there are obviously still many of them, big company employees seem to rely more on their employers to bring in top speakers. That doesn't help small company folks, but it removes a chunk of the audience that the meetups depend on to thrive. Even then, organizing community meetups can be a major job – getting venue/food/drink sponsors, herding presenters, etc. – and it's easy to lose steam. Like Marco said – there's no single factor, but my sense is that both have been affected over the last decade or so.