Concerts used to be packed when there were 1 or 2 concerts a year and sometimes even longer gaps. People just don't like going to concerts frequently. Organizers are treating concerts as a cash making cows and organizing concerts after concerts to make some cash out of it - along with the artists. It's like the goose that lays goldern eggs you have to wait till its cycle to get the golden egg. Audience will go to 1 or 2 concerts a year, but will get tired of those pretty soon. That's why thesedays concerts are empty.