Perhaps the closest term is “cognitive dissonance.” I don’t think current usage best fits your description, although the original event that inspired the term certainly does.

https://www.simplypsychology.org/cognitive-dissonance.html

Cognitive dissonance was first investigated by Leon Festinger, arising out of a participant observation study of a cult that believed that the earth was going to be destroyed by a flood, and what happened to its members — particularly the really committed ones who had given up their homes and jobs to work for the cult — when the flood did not happen.

While fringe members were more inclined to recognize that they had made fools of themselves and to “put it down to experience,” committed members were more likely to re-interpret the evidence to show that they were right all along (the earth was not destroyed because of the faithfulness of the cult members).

There is the sunk-cost fallacy, but that is more about investments. I don’t know if it’s refers to popularity like OP wants.