I guess white helmets are traditional if you go back far enough
This is not news…well…maybe to you and some other younger posters.
Arkansas had white plastic helmets with a red stripe down the middle for 5 years in the post WWII era. This was right after leather helmets were dropped from usage. The display you showed is misleading because it gives the impression that many of the early designs were also in plastic that were actually leather.
In the early era of plastic, most teams wore white helmets…probably because that was the color that most of them were made in early on.
Here is a good link to see the history of our helmet designs as they really looked: