You can't really call them nomads when it was supposedly 2 million people, continuing to have children and grow in population every year, moving around in a fixed area over 40 years.
Look at what happened at the original woodstock after just a few days.
40 years and not a single trace? How many animals did they supposedly sacrifice on a daily basis? Where are those remains? How many people died in that time frame? Where are their remains? How much trash do 2 million + people produce on a daily basis? Not a single trace? No broken pottery? Not a single speck of evidence they were ever there?