Now that the dubs have had a taste of zoom they are barely getting 60% attendance at the meetings. Its not surprising that a lot aren't attending the conventions.
Some of the old style conventions are bad enough to leave emotional scars - years later, due to the lack of comfort and care for the attendee's, so unless the convention is in a convenient, comfortable location, why travel and put yourself through an unpleasant ordeal?
The Sydney, Australia 2003 international convention was the last I ever attended. Some people travelled up to 3 days in buses to attend an over-crowded, open air venue in the middle of summer, an hour from the centre of the city. You had to bring your lunch and take home the rubbish. It took 15-20 mins to walk from the train station to the venue. At the time I thought it was a disgrace to expect people to suppport such a badly planned event.