I agree that the film is great and I like the format, but the Instax Wide camera itself leaves a bit to be desired.
But if it makes anyone feel more optimistic about the film, I think another place where it gets a lot of use is in the fashion industry. Photographers don't take Polaroids as test shots anymore since it's all digital for the most part, but I was watching Project Runway (shaddap, I like watching them sew) and it seems a lot of designers take instant prints of different looks on different models, and then these get tagged to the garment bag for the show. They all had Instax Wide cameras (I think the minis might be too small for their purposes). I just googled this to see if it was just a Project Runway thing or more common amongst more established designers. I didn't find much about that (though the Instax cameras do seem to be marketed towards fashion designers who are into all retro things these days), but there does seem to be a weirdly strong presence of Instax in fashion - given as prizes, used by fashion bloggers and even aspiring models.
What does this mean when the retro fad goes away? Well, the bloggers might not use them anymore, and perhaps not the models either, but the designers might still use them because there's still a need for an instant print.
I dunno, I'm just going to ride the wave for as long as it lasts