I work in a school (admin) and just booked some teachers for an upcoming conference. It's massive - 4 days of sessions 8am to 8pm, 7-8 different streams running concurrently, literally hundreds of speakers. Obviously, it's all online - so basically it amounts to hundreds of hours of Zoom presentations. Part of the deal for attendees is that they get access to all the resources (videos of all the presentations) are available to them for a year afterwards.
In a previous life I did a PhD and went to several academic and subject conferences, including a couple of massive ones. They were great experiences. The presentations were often good but the real benefits were the networking, the social time meeting a whole range of people I'd never met before including those at the top of the heap, and the opportunity to travel to places I'd never been before. I presented a few times and while I wasn't paid, the conference fee was either reduced or waived. The conference proceedings came out as a paper report - only the real headliners / events would have been filmed.
Are conferences of this type ever going to come back? For me their true value lies in the networking, face-to-face socialising, informal contacts etc. I can't imagine that sitting in your bedroom watching someone make yet another Zoom presentation is is going to be anything like the same experience as actually jetting off somewhere, to meet loads of like-minded people, to see some of your inspiring 'heros' presenting their work in real life, to make the contacts that will help push your career forward. What's going to take their place? if anything?