Anecdotal experiences are basically just that. And if someone doesn't have a power adapter and a cable why would they buy something other than what would fit the new cable that is included?
How many people do you think don’t have an iPhone charger at all that bought the iPhone 12 series? It can’t be very many or we would hear a much larger group of people complaining. It’s just a few on an Apple forum and Reddit.
If your a smart consumer, you know what’s in the box. I know what i am buying before I make $1000 plus purchase. Then you make a wise buying decision, and price out what it would cost you to make the most of it. If you don’t have any iPhone cables or bricks at all (I can’t imagine that group of people is very big at all), then you price out what saves you the most money. Wise buyers know what they need. Again the number of people that will need new cables and bricks is so small.