I wonder if any of the 260 complaints about Lady Gaga's performance on The X Factor were about the death of the avant garde, because that's mine. If this doesn't get me in Pseuds Corner, nothing will. Indeed, other female performers have garnered more complaints, so if Gaga is working overtime to shock us, it just isn't happening. We are familiar with the panto of The X Factor and with Gaga's turns. We expect her to look bonkers, cram in a ADHD medley and probably get naked. The soundtrack/product that comes with it is pedestrian, but her USP is that she doesn't have to look pretty all the time.

Of course her hint of freakshow fits in perfectly with a good old-fashioned variety show. It's all very postmodern, for although she may reference Andy Warhol as easily as she references Miley Cyrus's flesh-coloured bikini, she can be incorporated into primetime TV. Gaga is deemed suitable for "a family show". The promise of subversion is brought into the arena of light entertainment and demands little more than that we applaud the spectacle.

To demand a bit more from the audience, that they work it out, even stay with it, is not where it's at. When Lou Reed died, I watched some Warhol movies on YouTube and one wishes Warhol were still alive to see the comments. The YouTube generation are baffled by Warhol. A film of the artist eating a hamburger is exactly that. "WTF? Is this it?" they demand, short-changed. "Is that all there is?" Sometimes.

Reed's death has hit my generation because his presence anchored us into a time and a place when the avant garde was still meaningful. He was a touchstone of what it means to be modern, a significant and uncompromising artist whose works challenge social and artistic values. The Velvet Underground could have been formed at any time since 1966. They still sound utterly new. His death made us remember the music that made us want to leave our small towns and our small lives, a time when transgression was not simply a marketing technique.

The insane focus on whether he was nice or not seems misplaced, an attempt to jerk him back into the comfort zone. His music took us to dark places and we wanted to go. "Here is a song about taking heroin that is just like taking heroin," we wisely told each other on the bus in our school uniforms. "Here is a song about changing sex," we nodded wisely. He was not our mirror at all, but rather our compass. Now we have lost our bearings.

He did not need to explain himself in interviews, the work is there, already divided into the listenable/hits and the unlistenable/difficult. But here was a man whose cultural value far exceeded his commercial value.

There is not much of this any more. Marketing is now part of what artists do. They "play" with the market; their lifestyles and rebellions key into the corporate world. Art about art, art about money and value is now familiar. It was easy enough to walk around Damien Hirst's big retrospective and see precisely the point at which the money becomes both subject and object.

Grayson Perry's Reith Lectures have been poking at this can of worms, with Perry himself the most slippery of worms, wriggling between the roles of establishment insider and snarky outsider. He says we are at the end point, where the avant garde no longer exists. Rather, he evokes a horizontal, flattened-out globalised art world. Here sincerity is but one tactic, shock another. Innovation is more likely to come from technology than anything that artists are doing. Artists, he explains, operate as the shock troops of gentrification, moving into an area and clearing a path for developers. The web, he argues, echoes Joseph Beuys' famous statement: "Everyone can be an artist." Perry's view of art history is not one "ism" replacing another. Rather, we are living with all of this in the present. It is almost as if postmodernism has finished off the avant garde completely.

The jolt of Reed's death is to do with this. Lou Reed was avant garde precisely because he came out of modernism, because he changes for ever how things look and how they sound. A lodestar. His loss resonates because we can vaguely recall a time when not everything had been subsumed by the market.

So we are remembering his songs as if we heard them for the first time. Actually it's fitting. No one who ever heard the Velvet Underground could unhear them.

Watching Gaga writhe on the neuro-disco is a daft parody of Walk on the Wild Side. Amusement. Art does not have to be about transgression, it can be about anything – of course, it can. But look at us mourn the time when it felt that way; this loss is immense. As Robert Hughes said in the 80s in The Shock of the New: "What does one prefer? An art that struggles to change the social contract but fails? Or one that seeks to please and amuse and succeeds?"

You can answer that by pressing the red button on any remote.