I'm ancient enough to remember that when you took your grocery list to the grocery shop, there weren't many shelves that had packets of whatever for sale. Mainly the store had a whole series of large bins: one for flour, one for sugar, another for salt, etc.
You read out the list and the man would scoop up what you had ordered and put in into a brown-paper bag.
In today's world, that business-model is too labor-intensive. Better that you buy a standardised amount of product that a machine can measure out more cheaply and more speedily than any man can. But that product now has to travel the country instead of just back to your place, so it needs more robust packaging, and that packaging needs to be labelled clearly so you know what you are buying. That entails an inner plastic, sealable bag, and a firm cardboard printed outer packaging.
Progress? Perhaps.
But these numerous little exceptions don't invalidate OP's observation, wherein: Our needs have broadly changed, and thus so has our packaging.
I have an issue with disposable plastic food containers. So obnoxious. Some processed food has more packaging than actual food. Like plastic sushi boxes with the stupid plastic grass between the pieces.
A recent plastic bottle and aluminium can tax was introduced in my country, thanx to the EU, which has led me to change my behaviour from avoid to avoid at all costs.
Scientists found microplastics in clogged arteries. Soon we won't have just high cholesterol, but also "high plastics" in our bloodstream, as if plthalates that were linked to high cholesterol were not enough.
That would definitely get us rid of shrinkflation.
Egg in plastic container with lid
Burger wrapped in 3 layers of paper and one layer of foil
Above put into plastic bag with napkins
20 mins later all in trash all of which happens 10ft from cashier.
Crazy bad