As a nonbinary person, there's something uncomfortable about your comment that I can't quite put my finger on. Maybe as an inroad I'll quote this sentence:

Plenty of goth/punk girls rocked a look that almost certainly would be called “non-binary” today.

Now the issue I have with the above-quoted sentence is that nonbinary isn't a "look", it's a gender identity (or in my case, since I'm agender, the lack thereof). And I think maybe that's my issue with your comment. You seem to be saying that people are choosing to say they're nonbinary when really they're just gender-nonconforming. And I think that erases the fact that nonbinary people actually exist. Are we getting more recognition recently? Certainly. Are more people realizing that they are nonbinary because we're getting more recognition? Absolutely. But is everyone who is gender-nonconforming just "deciding" to be nonbinary? No, I don't believe they are.

Also, I binge read the book Beyond Pink and Blue (the one !transenby_liberation@hexbear.net is doing a reading group on recently) and it's caused me to think more about gender than I have since I was questioning. The author, Leslie Feinberg, is pretty clearly nonbinary, but for hir it's pretty clear that gender, gender roles, and gender expression are very much tied up together, whereas the modern conception is that they're distinct things that should be pried as widely apart as possible. I used to believe they were distinct things, and I still sort of do, but reading that book has made me rethink whether you really can separate gender, gender roles, and gender expression in any meaningful way in the real world. It's been a little wild.

So this has all been to say gender is a wonky, confusing mess, but nonbinary people do exist, we always have, it's just that now more people have heard of us and so can maybe put words to their feelings, which is a very liberating thing to do, let me tell you.