As others have pointed out, I believe that it probably has something to do with significant information appearing first (on a left to right interpretation). So,

As others have pointed out, I believe that it probably has something to do with significant information appearing first (on a left to right interpretation). So, 4,732 tells us that the number is in the 4700 range first, followed by the less-significant 32. I don't know if this explains how it became this way, but it would make sense in explaining why it remains this way.