Agree with you to a large extent - modern society is structured in such a way that personal change against the grain is difficult. It is down to businesses to be sustainable (and governments to incline/compel them), not individual consumers. Effecting ecological change by atomised personal choices is like trying to build the Hoover dam by individuals chucking pebbles in the Colorado river.
Having said that, there is lots you can still do. I’ll try to pick up on the main points in the thread.
Main point is don’t sweat the small stuff. A bit of cellophane round a pack of bar soaps is far preferable to a plastic shower gel bottle. A lot of plastic bottles don’t actually end up recycled due to contamination in the recycling process. Plastic is a waste product of the oil industry anyway, and petroleum isn’t going out of fashion any time soon. They will always be surplus waste fractions of petroleum products for plastics manufacture, as long as we are so oil thirsty. So try to reduce both counts in parallel, but don’t let the perfect be the enemy of the good (so you end up say driving 12 miles to buy a glass bottle of something than a plastic one in a shop in walking distance).
Totally agree with the poster who said that being totally frugal is the best thing you can do. Minimise consumerism, buy mostly second hand clothes and goods and mend things when they start to wear out. Stitch up small holes in the toes of your socks; get some bondaweb to mend the frayed areas in the inner thighs of your jeans and stitch to reinforce. Cotton is immensely resource intensive - pesticides, water, fossil fuels, bonded labour… get as much life out of clothes as possible.
Shampoo - Lush shampoo bars last for months, so do actually work out good value for money. I don’t recommend the “Friendly” bars though… they seem to clean my hair at the “lank and oily” end of the oil spectrum, but don’t touch the greasiness at the “waxy” end of the spectrum, so it’s gunky and ganky after a couple of weeks. If conventional shampoo is the only option, get the biggest bottle you can to minimise the plastic surface area to volume ratio.
Milk - either buy organic milk in large pitchers (organic milk is less resource intensive), or buy the huge 6-pinters of regular milk - choose ones at the back with longer use by dates. If you don’t use enough, either freeze (decant in to smaller bottles 3/4 full) or make yoghurt. Just buy a tiny tub of Yeo Valley natural bio yoghurt to get started.
Deodorant - try this out on a day you’re pottering around at home and not facing the world. Get a small jar, eg single serve pot of jam. Add a spoonful of bicarbonate of soda and a few drops of lavender/tea tree oil. Stir. Put a pea size amount on a damp face cloth and apply to armpit. Costs pennies and it keeps me whiff free till the next morning (though it’s not anti-perspirant).
Beeswax wraps - just use a bowl with a saucer on top, or pick up tupperware in a charity shop.
Produce bags - put the produce loose on the conveyor belt, or make drawstring bags out of old voile curtains or shirts. Buy wonky veg, even if it comes in a plastic bag. Perfect/premium grade fruit & veg is hugely wasteful. The trend towards wonky veg is an enormous step to cut down waste in the freshproduce industry.
Water bottles - you don’t need to spend anything near £12. I got a silicone covered glass bottle from Home Bargains for around £3. Even just reusing a plastic bottle is fine till you can get a permanent one.
Meat - buy from the butchers’ or Morrisons where you can take your own tupperware to the counter. Same for cheese/fish/deli items.
Laundry detergent - buy powder. Aldi is cheap and effective and comes in a cardboard box with no plastic handle. Use a bit less than recommended.
Coffee - drink in the cafe with a ceramic cup. Or look out for a thermal camping mug in a charity shop, they come up all the time. I got lucky and found my Contigo for £1 which is totally leak proof. Take a cloth napkin and a camping (or regular) cutlery set wrapped up when you have lunch on the go.