Can't speak for anyone else..... only myself. Over the years of 2019, 2020 and 2021, I have placed an average of 74 orders each year. I have paid $0 shipping and all were delivered. I would guess that each shipped order cost would start at about $15 each - Via Fedex and/or UPS. $15 x 74 orders would cost around $1,110 per year. Now, the $99 - $130 Prime fee looks to be a better deal for my use. And, the shipping cost has gone up. Now the average seems to be about $18.
Amazon works for me and so does Prime. If it does not work for others, then they should not use Amazon or Prime.