I have to agree with Rick (OMG - somebody write this date down.)
Bands should never 'cater' to the fans when it comes to their music and how they present it. Otherwise it would be an all hits all the time fiasco.
For musicians to streatch, grow, change and mature, they have to do what they feel is right for them. As an artist if you create something just for someone else (like an "intended" fan base - be it one person or millions) than you're not true to yourself and the creativity you possess.
It is the artist's creativity and ingeniuity that makes them so special. When they do cater, such as when record companies try to insist on creative control and demand 'x' amount of records in a specific time frame, then the music almost always suffers. You can't be forced to create. Just because someone wants a new album from an artist doesn't mean they are going to get it, nor that the artist "owes" them the product.
Touring is the most lucrative means for musical artists to share their music with the fans. Recordings are the other way. And with file sharing these days, recording is not very lucrative except on an extremely grand scale. Not something our genre's favorite artists are able to achieve, except in very special circumstances. It's sad for so many gifted musicians, but unfortunately true. Schlock sells, genius takes time.
Touring, on the other hand allows a creative commune with the fan base. Sure the songs may be from material that is not new in some cases. But it is personally packaged for each audience and delivered with as much charisma, technical skills, and creative touches as possible. Having altered or changed line-ups also changes the music and the character of what they are presenting. It's made it new again, just in that light.
So, long story short: No, bands don't owe us a thing, just as we don't owe them our hard earned money, time and adoration, should we become disillusioned about their supposed motifs for doing what they do. In other words, if you don't like the program, change the channel.
And in the case of Yes - they have almost 40 years of material to work with, as well as the wealth of solo material each of the musicians have generated. That's a pretty damn big playlist. It's not like they only have 3 or 4 discs to choose from.