Artists that use the same song structure...

"Avant-garde is highly subjective. To some its recordings of steam trains; others its Captain Beefheart, still others U2. To be honest, I find most "avant-garde" to be highly self absorbed. Just my .02"

I suspect you possess the platitudes when one is to elucidate avant-garde...again, very predictable.

Phasecorrect, I agree--good is good and bad is bad, regardless of whether it's primitive, complicated or somewhere in between. Of course, it's subjective and there are no absolutes in this matter.

Well, .02 is more than most have contributed.

I think it's fair to point out that "avant-garde" is hard to pin down when discussing music. Does Phillip Glass qualify? If so, he probably fits the OP's question reasonably well as much of his work follows pretty formal structural rules. Actually, while I don't profess much depth of knowledge of modern "avant-garde" composition, it kinda seems to me that a fair bit of it is formally pretty rigid, Schopenhauer is one that quickly comes to mind.

This isn't my listening hour "meat and potatoes", but I'll dip a toe in these waters from time to time.

"Phasecorrect, I agree--good is good and bad is bad, regardless of whether it's primitive, complicated or somewhere in between. Of course, it's subjective and there are no absolutes in this matter."

What a contradiction.