What they weren’t able to do was get gigs in jazz clubs. Many of those venues were drying up, as jazz’s receding from mass awareness was in full swing (save for the electric work of Miles Davis and bands formed by members of his various aggregations, and popular jazz-funk hits), and those that were hanging on weren’t having all that caterwauling in their establishments. So the avant-jazzers made their own infrastructure, using vacant buildings in Manhattan as rehearsal, performance and, for some, living spaces.
These spaces, with their wide-open floor plans, were repurposed from their former lives as factories and warehouses. Sometimes the actual owners knew about it, but that doesn’t seem to have always been the case. From this turf, musicians staged their own concerts, held their own jam sessions, and forged their own micro-economy. Eventually, word got out, and as is often the case, someone felt inspired to label this new thing. As is also often the case, the people being labeled weren’t all that happy with the label that stuck: “loft jazz”.