You make a great point! I just looked and today’s travel size tubes can actually be less than one ounce.
I was working from memory and going back fifty years. So sure, my 4 oz. recollection could be off. Don’t think so, though. 4 oz sort of sticks in my mind.
But given the tiny size of today’s travel tubes, the comparison with 5.1 oz. becomes more understandable. I did not consider their having reduced the travel size along with everything else.
I guess, moving forward, someday in future they will sell you only just an empty carton but charge regardless for a tube of toothpaste. Seems like some posters here would accept such a zero option deal with scant protest, and valiantly make effort to brush their teeth with cardboard. Do not count me among their numbers, but I’ll be dead by then anyway so what does it matter.
I don’t mind the changes so much, but it really pisses me off when companies try to hide it by manipulating the packaging, like adding big voids on the bottom of a tin.
Ultimately, though, the impact on me is negligible because I shop by unit pricing. The impact is the same whether they increase the price or decrease the quantity, and it makes it easier to compare prices between stores and types of packaging.