Before the pandemic, you already had some online graduate courses for example!
Sure. It was just not that generalised.
I guess here we must distinguish courses given to the young ones (students in their first year of their studies) to the advanced ones, including workshops, graduate and post-graduate events, and conferences.
For the youngest students, I always recommend a mixed program: do online what does not strictly require an on-site presence, and use the on-site time for new kind of activities (for instance active-learning-based sessions), or for stuff that cannot be done online (like lab classes). This is at least how I teach now to the young ones.
For the rest, I agree with you. I did the same as you related to conferences and workshops, and I have never attended so many events in a year. However, we don't enjoy them as much for the reason you mentioned: we always multitask... In short, we must make concession and try to stay disciplined (which is not easy). Also, great projects often originate from coffee-break discussions. With online events, this is not possible anymore.
Anyway, I stop here (for now ;) ).
Cheers!