Not sure if all consumers are gullible really but when looking at a spec sheet it is a clear item of distinction that they somewhat understand compared to other items eg ISO. Those aren't the customers for 1D/R5 series cameras but could be an issue for cameras like the R6.As a photographer and not a tech guy, I couldn't agree more. Considering that I could take my 6 MP pics taken with my original digital rebel, and crop them to about 2/3rds size, and make an 8 x 10 print that is tack sharp, I do laugh at the notion that the majority of camera owners would need even 20 MP. What it shows more than anything is how gullible consumers are.
There are definitely use cases for higher MP stills even if they aren't what your workflow needs. Yes, there is less need for prints compared to online resolution. Yes, you can take a shot with lower res that provides a great/sharp 8x10 print. Yes, we had no choice in the past about number of mp so made the most of what we had at the time.
The ability to crop heavily is very useful in situations where you cannot avoid getting closer or having an appropriate lens (can't afford it, didn't have it with you, can't change it to the better lens, etc) eg for birding or where I am shooting underwater with a 16-35mm lens and find something small to shoot but certainly doesn't fill the frame and clearly can't change to my 100mm macro setup
8k video is clearly not for everyone but offers a lot of post-production options that aren't available in any other format. Getting 33mp jpeg stills at 30fps is something that wasn't possible before. The res of 4k frame grabs probably wouldn't be as useful.
If you had a choice of 20mp or 45mp when printing large then you would clearly prefer the latter if possible