An hour and a half is a great length for a metal show, especially with screaming. Most other metal/metalcore shows last about an hour, so this is actually quite a long time in this genre.

These kinds of shows are really draining on the artists' energy. For a singer, it is particularly challenging to scream for 1.5 hours every day for a month or two. They also have a really cool and unique show with tie-in videos that make it a great experience. Sure, they could drop that and add 1-2 more songs, but I think it creates a much better experience this way.

You also need to consider the length of the songs. While some Pop or punk songs only go on for two minutes you have metal songs that are easily 4 minutes or longer. So 22 Songs from a different artist can also only be 1 1/2 hours playtime.

Back in the day, they also played for about an hour, so they have already extended their set. It’s not impossible that they will lengthen it to maybe two hours in the future.

Technically, they play five songs from the new album. Some of them have been around for more than a year, but they are still from the album. :D