Given how prevalent plastic is, my suspicion is that glass is more expensive than plastic. Single use glass seems like a waste, though I haven't run the numbers.
Unless we can get to reusable glass. Living in US and walking the aisles of the local supermarket, I don't see how that's possible. The glass-packaged foods come from all around the world, with each company apparently intent on having its own distinctive glass shape. As 'recyclable' material ends up in the landfill more often than not for cost reasons, it seems a monumental task to build a 'reverse distribution' path to send back glass containers thousands a miles away to their original producer for reuse.