Frank Zappa hit the nail on the head:
One thing that did happen during the 60’s was that some music of an unusual or experimental nature did get recorded and did get released. Now look at who the executives were in those companies at those times – not hip young guys. These were cigar chomping old guys who looked at the product that came in and said, “I dunno. Who knows what it is? Record it. Stick it out. If it sells, all right!”
We were better off with those guys than we are now with the supposedly hip young executives who are making the decisions about what people should see and hear in the marketplace. The young guys are more conservative and more dangerous to the artform than the old guys with the cigars ever were.
And you know how these young guys got in there? The old guy with the cigar, one day goes – “Yeah, I took a chance. It went out and we sold a few million units. All right. I dunno. I dunno what it is. But we need to do more of them. I need some advice. Let’s get a hippy in here...” So they hire a hippy. They bring in the guy with long hair. Now, they’re not going to trust him to do anything except carry coffee and bring the mail in. It starts from there. He carried the coffee four times so they figured they could trust him. “Let’s give him a real job.” He becomes and A and R man (artists and repertoire) . From there, moving up and up and up... Next thing you know, he’s got his feet on the desk and he’s saying, “Well, we can’t take a chance on this – because its simply not what the kids want – and I know.”
The last time I know that the majors did that was in the 1990s and then they panicked and moved to the safety of boy and girl pop singers that they could market like the Monkees but without the depth or personality or staying power.