Clearly. And that's a benefit that we all want. And those 2nd and later uses of glass bottles aren't "free". For the particularly heavyweight milk (etc..) glass bottles, the bottles have to be collected and transported back to their provider, who then washes them, discards (recycles) the ones that have chips etc.. that make them un-reusable, and then reuses them. The return, washing, and inspection is (presumably) much cheaper than buying brand new bottles for each use but it isn't free by any stretch. Which is orthogonal to the point I'm trying to get at. I can identify two features beyond cost for why plastic is desirable over plastic. This isn't an argument in favor of sticking with plastic - the point is that these other features delta from glass needs to be minimized as well for glass to start substituting in large volumes for plastic. 1) plastic weighs (a lot) less than glass. That's the point above. 2) plastic deforms and breaks in a friendly way compared to glass (glass turns into sharp pieces when it breaks, and doesn't deform in friendly ways). A washable glass bottle that didn't break (maybe it shatters the way that safety glass shatters, and only with great difficulty at that), that weighed the same as plastic - that'd be an awesome invention if it could be manufactured in something like comparable cost as plastic bottles. Or have a lifetime cost that was something close to all of the plastic bottles that wouldn't be made. Then the substitution would be easy. Without that equivalent technology, the alternative is for the stuff we buy to cost a lot more, so that its packaging can be a lot more expensive. Everything else being equal, "more expensive" is not a path to broad adoption. Changing fossil fuel economics that results in plastic being more expensive - that sound great to me as a vehicle for making glass more competitive. (For me and my family, we broadly choose glass packaging over plastic as we find that glass packaging is non-reactive compared to plastic. Stuff in glass bottles tastes better than stuff out of plastic bottles. And we pay for that privilege).