To be fair, some realms were created with old realms' names while having little to do with them, while other realms kept their original realms over the years while losing all that was associated with it.
Realms mature with time, many undergo outright metamorphosis, with the gradual decay of it's original population and replacement with others. Feels to me like few realms alive today are still very similar to what they were 5 years ago, let alone 10 or more. With declining densities and group mentality/tribalism, cultures also tend to be less defined, weaker, and more prone to replacement.
