That way each show is sort of unique, not the same exact show 60 times.
When you go to see a Broadway show, do you expect it to be different each time? Some musical performances are shows, some are concerts. There's a difference.
Many artists/bands change their sets each night, at least somewhat. There are certain songs that
must be played, and a concertgoer should expect to hear them, assuming the band cares about the people who pay to see them.
With respect to set lists, even if the band doesn't post them, the fans will. For a band that changes up their set each night, it doesn't really matter anyway. But for a band that does a
show, it's completely their call whether they want to post their set. If you don't want to know, don't click on the SET LIST link on their site, and don't visit setlist.fm
We never posted our current tour's set online, although the fans often did. Although the info was out there, and completely correct, at least it wasn't coming from us. However, once that tour was done, the set would be posted and served as an interesting look back at previous tour's songs, which often led to fan requests to bring certain songs back. And, we sometimes listened!
Bermuda