The origin of this 10x meme was (if I remember correctly) measuring productivity on a single task. It is not inconcievable that the difference between the worst and the best is 10x on a single task, especially for students. This doesn't tell us what the difference between the average and the worst/best, which would be more interesting. Also, it doesn't tell us if the best developer is consistenty 10x faster, or the worst performing developer just made a mistake with this particular task.

If you compare a developer solving his first task in an unfamiliar language/platform/framework, you will easily see this magnitude of difference compared to a developer with deep experience. But this difference will not stay consistent.