I remember back in the early 1990s when one book, I think it was Namor by John Byrne, had a questionable future because it was hovering near 100,000 in sales (the danger zone).
Today selling 50,000 copies a month makes a book a big hit. I guess a few hundred thousand readers came to the same conclusion I did a decade ago, and decided they would not pay exorbitant prices to be lectured at (and that was before the SJW nonsense was ramped up to where it is now).
100k was never the bubble even in the 90s. You are free to follow the link I posed elsewhere in this post to see distribution numbers both historical and present.
100k in the 90s was a top 20 title guaranteed, today 100k is guaranteed in top 10. Numbers are down but 100k a month was not the bubble in the early 90s.