Pi day is a thing, why would Prime day not be a thing as well?
Because Pi day happens on the same date each year and is therefore easy to observe, whereas "Prime Day" like you're proposing would happen ~50 times in certain years, but not at all in most other years, becoming less and less frequent as time went on. Not exactly a practical thing to celebrate
Because Amazon's "Prime" service is well-enough established internationally that that should be what most people think of first even if they aren't familiar with the fact that Amazon does this annually, especially in the context of "finds" and other word choices that imply shopping
Because you already knew today was not a day with three prime numbers because 2023 is not a prime number, meaning it was obviously something else
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