I do science me.Often, badly, along with my woeful maths, but bear with me.
I was about to pop these two fellows in the wheelie when I noticed something.
Accepting the left one holds 75cl and the other 70cl, the former weighed in at 550gm, whereas the latter was 320gm.
That... is quite a difference, and I presume a clear example of lightweighting.
What I can't testify to is the relative in-transit breakage levels, but as an example of what can do the same job for a lot less, and consequent freight energy savings, that seems significant.
