This is a list about cities, not civilizations. Nomadic populations can be included in lists that talk about those topics. There can also be a list of "oldest nomadic populations" from which cities are excluded.

I'm also confused at your 14,000 years comment... this isn't the age of any particular polity or ethnic group; just the amount of time since people settled North America. Across the old world, comparable tribes lived for much, much longer. And in Africa you can go back even further.

What exactly do you think should have happened here? Simply not allow lists of old cities? Or perhaps put in special entries for nomad tribes even though they're not, you know, cities? What's the goal that would have made sense but also made you happy?

https://en.wikipedia.org/wiki/List_of_nomadic_peoples