Grunge and punk were both counter-culture movements. The reason the original fans lost interest is once they became mainstream, they were no longer counter-culture, and they lost their purpose.
Furry fandom has counter-cultural elements, but that's not its reason for existing. So becoming mainstream is unlikely to turn off most current furries.
I actually think by making the fandom seem less oddball and scary, mainstream attention can only help. The quickest way to make people stop being afraid of something is to over-saturate the culture with it.
Grunge and punk were both counter-culture movements. The reason the original fans lost interest is once they became mainstream, they were no longer counter-culture, and they lost their purpose.
Furry fandom has counter-cultural elements, but that's not its reason for existing. So becoming mainstream is unlikely to turn off most current furries.
I actually think by making the fandom seem less oddball and scary, mainstream attention can only help. The quickest way to make people stop being afraid of something is to over-saturate the culture with it.