For anybody interested in this era of photography, the book "A Triumph of Genius" by Ronald K. Fierstein is such a brilliant documentation of the history around the Kodak vs Polaroid patent war.
It's certainly expensive, but have you seen what it takes to produce photographic film, let alone instant film? My guess is that there isn't much of a profit margin for them, even at over $2 per photo. Another thing: adjusted for inflation, SX-70 film is actually slightly cheaper now than it was in the 70s and 80s, despite the massive drop in market size.
https://www.youtube.com/watch?v=Lo_1pyQ7xvc