I have gradually wondered if the issue has not been in our obsession with plastic specifically, but our need for sanitation of every object. "We need a material that will preserve its shape in transit and operation; but we then want it to gently break down into nature when we're done with it." No matter what materials of what strength we invent, that's always going to be an oxymoron. There's a reason people criticize biodegradable materials as often falling apart.
Don't get me wrong, I'm sure medicine has made tremendous advances through the preservation of sealed instruments and drugs, especially for those with sensitive immune systems. But the 3000% thorough sanitization we keep of every single object we interact with has had a very gradual impact on our planet. I kind of want to envision just how fatal of a health risk it would carry if so much of our food wasn't triple-secure-wrapped, and whether that's comparable to the current impact of widespread plastic.
No, the problem has never been us at all. We don't run Coca Cola Co. We don't decide how laundry detergent is packaged. We don't manufacture excess plastic drums and lined tanks for unnecesary use cases. We don't flood the market with cheap dinnerware, plates, cups, bowls, etc.
Big corporations do all of that. Run by dozens of people who do not care what we think.
We're always trying to optimize and reduce loss/waste. Being able to have food sit on shelves for months without oxidizing or rotting has been a huge improvement in terms of food loss but it requires these biounavailable materials. If we use compostable materials for packaging then the clock starts ticking on them and storage facilities need to maintain stricter standards (i.e. keep humidity down).
The medical aspect is a big issue. You see what is consumed in an ER and surgery and then multiply that by a million/day and you wonder how much of this trash is being produced. Lawsuits over every little medical issue don't help reduce this. Fishing industry waste is another big issue for the oceans.