In some cases, like water, it's more about when the plastic will start noticeably altering the taste and properties of the food

That's why EU or at least Finland at least used to have separate labels; "best before" and "use by".

One was like "this might lose some quality after the date" and one is "please don't eat it, it might be dangerous".

Although the latter was still always erred on the sage side. Whereas grandma dismissed the bunch and just sliced the mold off the cheese and ate what was underneath. And it wasn't blue cheese — originally.

And rue the day if I threw out old milk instead of letting her make some home made cheese or smth.

In Germany, the best before date is not required for things like spices, and other food that will still be consumable even decades after packaging.