Cheaper is often because something was easier to make. Less materials and less energy.

That's certainly the case on a one plastic bottle to one glass bottle ratio, but I wonder just how energy efficient is making that bottle over the glass one? Twice? Ten times? A hundred? Then how many times will a glass bottle get reused on average? What sort of resources are used in the process of bringing them back and cleaning them?

This might be my bias as an Australian, tons of space but already having our natural wonder smashed by climate change, but I'm very uninterested in 'pro environment' moves that results in trading higher emissions for less land fill.

Although potentially an argument could be made that because ocean waste is less contained and more harmful than landfill, a 5-10% hike on plastic bottle drinks in low water polluting countries and using it to subsidise glass bottle drinks in high water polluting countries would be worthwhile.

Its a popular misconception that recycling and climate change are in opposition. Landfills are the biggest producers of greenhouse gasses after electricity generation, transport and agriculture.

The reduced carbon impact is one of the reasons to recycle, but your not the first person on HN that I've seen claim exactly the opposite.

(Of note, burning the trash and using the energy produced is also better for climate change than landfill).

Is it the plastic in landfills causing the greenhouse gases?

Probably mostly rotting food and other organic matter, maybe some fridges and other chemicals. But once you start recycling one thing, it makes it easier to recycle others as they share infrastructure.

But recycling plastic specifically uses less energy which in turn saves carbon.

Even burning the plastic as fuel is regularly cited by life cycle analyses as less carbon intensive than landfilling it and creating totally new plastic to replace it.

I'd expect there are lots of factors with glass. Making a new plastic bottle every time might be cheaper on a resource-use than making a glass bottle and washing it for re-use (which uses energy, and water) some average number of times before it gets broken (5? 20? 50? No clue). But it might not.

However, other factors include: labor; transportation & waste costs (glass is heavier and breaks easier); and labor-geographic efficiency enabled by lower transport costs—for example, you might choose fewer bottling plants farther apart for cost efficiency, so you can reduce overhead and concentrate your labor costs in cheap locations, rather than every town having a small bottling plant, or stores having fill-n-cap stations directly in them, or whatever.

[EDIT] that is, with lower transportation costs of plastic you might be able to concentrate production in places with cheaper labor.

Another challenge with bringing back reusable glass bottles is that that approach belonged to an era with more local brands and a smaller variety of products. There were a few brands of soft drink that were all being mixed and bottled at local distributors, and cities had their own breweries that mostly only distributed locally.

Now that we have enough different brands of soda and beer to cover three sides of a convenience store, all made and packaged at one location and then shipped across the continent, I don't know that glass can be considered a less wasteful option. It's not just about the actual piece of packaging, it's also about how much diesel fuel is being burned in shipping such heavy packaging over long distances.

Glass return schemes basically require standardized bottles. That's how it works in part in Germany: there's a small number of standard shapes of beer bottles, breweries get their share of bottles from return locations around them where possible. It breaks down with more and more breweries using custom bottles, which do need to be sorted out and returned separately, over large distances.

Reusable glass bottles also mean that you either bring the exact bottle to the exact retailer to get refilled with the exact product, or brands lose the ability to use the container for advertising and brand identity.

Even the frou-frou dairies that let you bring in their reusable bottles only want you to bring back their reusable bottles with their stenciled logos on them.

In the UK there is (still, in some places) milk delivery to the doorstep in 1 pint bottles. These are all a standard size, and they're all branded by the dairy. But interestingly the dairies are perfectly happy to use another company's bottles if they end up with them - branding be damned.

When I lived in a place with only one delivering dairy, this was quite rare. In Liverpool, I'd say that 10% of the bottles I get are 'foreign'.

In the US, I quickly accumulate 3-4 Stanpac glass bottles that are almost entirely identical, except for the indelible sintered labeling, and then I get behind on taking the right one to the right store and throw them out.

Which is something that could be solved by regulation mandating standard bottle shapes. Environment is more important than "brand identity".