I totally agree with you @Isabela in that we loose not only in-person interaction but also high-quality experiences in a completely virtual version. Watching concerts on my TV at home was OK, but very different from a concert hall experience. I also miss touching and testing various interfaces/instruments in demo session.
That is why I think local/regional hubs may be an interesting thing to explore (what I called hybrid conference over here). The challenge, however, is how to make this work well for everyone, particularly if we want to make it work both for people in hubs, but also people choosing to attend completely online.