Glass is in no way environmentally friendly. It takes a huge amount of energy to produce glass, and a singel glass bottle requires a lot of it. PET bottle recycling is the closest we got to a functional plastic recycling system.
You make a good point and it can be interesting to know how many use of a bottle are required until it becomes more energy-efficient compared to disposable plastic, etc.
The shift to the all plastic packaging paradigm was made when companies found out that they could simply let the consumers deal with the packaging once the product was consumed instead of having to get it back from their hands and process it. Hence the modern plastic dystopia.