@Selkie: no new input from me, but an observation or two on the second two of your three things noticed:
these phenomena are, imo, symptomatic of a nation or world of people ever less prepared to their thinking for themselves, ever less prepared to make decisions for themselves, ever more prepared to let others decide for them what is best, or most delicious, or easiest to prepare, or or or or
Many people nowadays in industrial nations are not capable of cooking for themselves, have never learned to do so, and why should they: the supermarkets, as you have observed, make any efforts at doing so superfluous.
And, if all the turkey you've ever seen is as slices from the supermarket fridge, how the hell can you know how to serve or slice one?
Even if it means a lot of extra work, a lot of blood sweat and tears, as one says, I always prefer to do things myself, and not have someone else decide how much garlic is suitable for a sauce, or how much MSG I can safely be abused with, and so on and so on and rant and rave .....