The Coca Cola bit is a myth. There are a lot of depictions of Santa in a red suit before Coca Cola used it in advertising: https://publicdomainreview.org/collections/a-pictorial-histo...

Not a myth but true - https://en.m.wikipedia.org/wiki/Santa_suit

The site you link to even claims that it is a myth:

"This change (to the red suit) is often mistakenly attributed to... the Coca-Cola Company...the red suit was shown on the covers of Harper's Weekly at least forty years before".

Coca Cola can however probably be given a fair amount of credited for making this the ubiquitous look.

Aha, my bad - though fair to say, it was born out of marketing and darn good marketing at that (worked on me).