Maybe it’s your location. Bay Area Amazon is still consistently hitting its one day and two day delivery targets.
Maybe San Francisco is. The Bay Area in general does not get prime delivery speed, despite Amazon's assurances to the contrary. They don't even try.
Not only that, but Amazon long ago stopped packaging the stuff they ship out to prevent damage to it. Whatever comes from Amazon will come with shipping damage. If you return it, Amazon will ship you a replacement in equally inadequate packaging with similar resultant shipping damage.
If you're hoping to receive an item that meets the absolute bare minimum standard of arriving when the vendor says it will, without obvious damage from shipping, it's necessary to avoid Amazon.