I think the local club/audience dynamics changed. These clubs in the late 80s/early 90s could fill up a small venue with an out-of-state headliner and a few local supporting acts which gave an incentive to regularly do these shows. 10 or 15 years later I think that became far more difficult as fewer people wanted to see loud bands in a small club, which drove the DIY bands back into DIY spaces. I remember the last time I went to TTs in the early 2010s and very few young people were there to see the rock bands.
There were always DIY shows percolating at the edges in the 80s, sometimes with well-known names participating. I saw F.O.D. in wide hallway on the 2nd floor of a beat-up Allston commercial building that was sometimes used for art shows and poetry readings.