According to the article you posted, they further stomped the fermented grains with their feet, which I presume introduced some rather fascinating bacteria and such. The modern day wild ferments are interesting in their own right. I'd imagine the ancient versions were fairly wicked in flavor. Lol.
Some Belgian brews are strictly wild fermented. They have large windows opened to let the wild yeast in.
While reading this I thought of perhaps the most unfortunate brewery name. St Louises Griesedeick Brothers Brewery Company.