Why don't we go back to glass bottles?

Good question, plastic has toxins in it if you reuse them. That is what the triangle on the bottom of some plastic bottles mean, and the number inside the triangle means. Safe to drink out of 1, 2 and sometimes it has a higher number inside the triangle. Back to the question, it's more expensive I guess. Plastic is more poplar, doesn't break or bust as easily, not as heavy.

It would also help cut back on petroleum usage! But anyways, glass is much more expensive to make and buy, its more difficult than molding plastic