Making industries/factories/companies accountable for environmental pollution is easier, logistically/politically/financially, than making individuals accountable. So yeah, people are shit and they want this but fixing the problem is easier if you go after the industry and tax the externalities. Plus it’s not so black and white. In my neighbourhood people want to make environmentally friendly choices but when you go to the market you’ll find no options without plastic packaging, food chains refusing to serve in my own metal containers etc etc.
In a similar vein, a majority in a country can choose to oppress the minority but that doesn’t mean government should let it happen because the people made the choice.
And because it's often the only option. Here's a question for you, which one happened first? A) someone packaged a good in plastic or B) someone bought a good packaged in plastic?
Its a third option:
At some point someone decided to package an existing product that was not usually packaged in plastic, in plastic. Consumers decided the new way of packaging was superior and everyone adopted it to keep up.
I have to disagree that all changes in the details of product disbursement originate from an increased benefit to consumers (rather to to benefit producers as your comment implies), but I cant deny that there are substantial benefits on both sides once you ignore the externalities. Regardless, it is practically impossible to avoid buying most goods without at least a small amount of plastic packaging, so even if the masses were capable of organizing to effect change regarding packaging, someone has to recognize a market for it and change practices accordingly.
It's a problem of scale, convenience, hygiene, etc. "back in the day" stuff like paper bags or waxed paper was a lot more common, but the volumes were also much lower, the availability of luxuries like idk, takeaway food and soda was much lower, etc.
Going back will mean going to the market, getting fresh vegetables and potatoes and shit, and put them in either paper bags or reused burlap sacks. I think an individual's biggest contribution would already be changing their food habits; stuff like keto, primal diets, vegetarianism / veganism are a step in the good direction. Assuming you cook your own food, instead of idk, grabbing a McD's salad (in a plastic container) or pre-packaged vegetables (plastic bags).
The new packaging products aren't better, just cheaper. And volumes of vegetable sales have only increased.
My brother worked produce when they switched from paper to plastic packaging. Moisture issues ruin lots and lots of produce at a much higher rate in the plastic.
The other driver is the industrialization and centralization of production. You need plastic packaging and controlled delivery to ship your produce from irrigated desert in California to Maine. Of course in the process you kill off all of the regionalized produce growers as the whole supply chain needs to adapt.
Even meats are this way. Meat is packaged in plastic because the industry was allowed to consolidate to a few fly-over states with awful labor practices. When I was a kid in NYC, whole sides of beef were delivered and cut in the supermarket or butcher. No packaging required until retail, and retail packaging was mostly paper. Now some dis-assembly worker butchers meat in Colorado or Iowa, which must be shipped in cyrovac plastic to the retailer.
Scenario: I need to buy some water or milk. I go to the market... what are my options? My grocer does not provide water in plastic or metal bottles, and no longer provides cardboard milk cartons.
Scenario: I need a quart of oil for my car. Packaging options are: 32oz PET bottle.
Scenario: I need a laptop computer. I order it online. There is no way for me to tell what packaging is used. I open the box and the laptop is protected by polystyrene and accessories are in taped plastic bags.
Longer answer: reduce your buying habits. Keep your laptop/phone around for longer before replacing it. Buy second hand or refurbished devices.
Do you need to buy water, or could you drink (filtered) tap water? Do you need to buy milk, or can you replace it with an alternative? Soy and oat "milks" are different, but serviceable replacements. Avoid almond and other nut "milks".
Sometimes you can't really avoid the packaging, but you can make sure the product in that packaging has a smaller environmental impact.
As for motor oil, most cars only one oil change per year, so that bottle of oil isn't the worst item in your example. But you should probably drive less.
In other words, ignore the problem and do something else that gives a warm fuzzy feeling. Replacing milk with a more expensive, processed alternative has nothing to do with a plastic bottle.
The global solution to reducing plastic packaging is to reduce the use of plastic packaging, mostly by using cardboard and glass instead. That's driven by manufacturing, not consumer action.
You were specifically asking from a personal perspective, so I gave answers from the same perspective. That does not mean that I discount the impact from corporations, in any way whatsoever.
Lifestock farming is one of the biggest contributors to climate change. By choosing alternatives, this contribution can be lessened. I very specifically said not to buy nut milks, because they're also rather bad for the environment, especially in terms of water usage. Soy and oat milks have lower impacts than dairy and nut milks.
Just because your individual action doesn't make much of a difference in and of itself, that does not mean we should just give up. Obviously it shouldn't be a case of ignoring the big polluters just because you did a small thing, but by changing our habits, we can use consumer demand to change the production and packaging practices of corporations.
Individual action does make a difference. Everything counts.
In a similar vein, a majority in a country can choose to oppress the minority but that doesn’t mean government should let it happen because the people made the choice.