It's not subversive to fight for the irrelevance and marginality of an art which is already marginalized. Being subversive means undermining a dominant ideology.
What's known as avant-garde today is the posturing of a highly-placed artistic aristocracy, who've been through the academy, whose thoughts and actions often take place within the academy or other approved institutions such as government regulated non-profits. Which turns "avant-garde" into a contradiction.
Those who work toward the unpopularity of literature; those who make the literary art more jargon-filled and inscrutable, follow a concept of avant-garde which has been out of date for fifty years.