I'm happy to pay the $15/month just to have the capability to have stuff shipped to my door overnight for free. There are months where I don't order anything at all. Compared to rent or food it's a drop in the bucket.
I'm saying I'm personally happy to pay for the subscription if I don't use it, and don't care if they move to a "refill" model. So my take is that not all the prime customers are scammed.
That being said it's been a while since I did the signup flow, maybe it's gotten way worse, do you have an example?
Amazon chooses shipping defaults to benefit themselves.
With prime I have to manually select the shipping speed to get it the fastest.
Without prime, it defaults to faster shipping that you pay for. You have to manually select slower shipping to get the advertised "free super-saver shipping"
For me, most products get delivered in 6 days with Prime. It has stopped making sense to pay for the Prime subscription. It's cheaper to pay for faster shipping, given that I only order 1-2 items monthly.
One nice part of shopping on eBay is their proximity sort. IME this tends to minimize shipping time (and, of course, carbon footprint). When I order something locally from the LA area, it’s usually there the next day or two even with free shipping.