But they're not random, that's the point. Each one had goals and motivations behind it, each one had consequences, and some of them were better than others. If you want to say "the coin flip happened thousands of years ago," how far back do you want to take that? Is it a "coin flip" that we happen to be on a planet with 12 lunar cycles in a typical year, which gave us natural preferences towards 12 unit cycles for keeping time? Is it a coin flip that we have ten fingers and ten toes and that's why we use base ten for our numbers? Sure, maybe (although it's worth noting that the religious perspective, which this system was deliberately made in opposition to is that that isn't random), but at that level we can say that about literally everything in every aspect of human society. That doesn't mean its not worth looking at some of the more immediate causes.

But they're not random, that's the point. Each one had goals and motivations behind it, each one had consequences, and some of them were better than others. If you want to say "the coin flip happened thousands of years ago," how far back do you want to take that? Is it a "coin flip" that we happen to be on a planet with 12 lunar cycles in a typical year and a 24 hour day, which gave us natural preferences towards 12 unit cycles for keeping time? Is it a coin flip that we have ten fingers and ten toes and that's why we use base ten for our numbers? Sure, maybe (although it's worth noting that the religious perspective, which this system was deliberately made in opposition to is that that isn't random), but at that level we can say that about literally everything in every aspect of human society. That doesn't mean its not worth looking at some of the more immediate causes.