If you went to any thrift store in the country in the year 2000, and you would have found branded merch galore. In the 1980s, companies realized the benefit of getting customers to prominently promote their products, so they started distributing branded merchandise in huge numbers. 

But back in the 1960’s it would have seemed crude or crass to be a walking billboard unless you were a professional athlete or NASCAR driver. In 1967 Adidas didn’t even have their famous logo on their shoes and new tracksuit and their name certainly wasn’t prominently displayed. At the time they were simply promoting the “3-stripes” design. Adidas introduced its Trefoil logo at the 1972 Olympics. But it wasn’t until much later that flashing the brand name on your clothes became fashionable.