I signed up for Prime a over decade ago because of the reliable 2 day shipping. It worked pretty much as described. It was great.
Shipping is no longer 2 days on most items - "Prime" shipping can now take 7 days. Amazon advertise same or next day shipping, but it's really only for big ticket, occasional purchase items. Most everyday purchases now take 3-7 days, the same as without prime. They show the prime badge, but if you log out you can see that non-prime members get the same shipping.
This feels really dishonest. Amazon pretend that you get huge shipping benefits from Prime, but it turns out you don't anymore.
For the first time, I've cancelled my prime renewal. What, exactly, am I paying for these days? Walmart offer next-day free shipping on the big ticket items too, without the membership.