The evolution from leather-soled shoes of the 19th century to the sneakers people wear today started slowly, then built momentum. Many of the big names in sneakers today got their start surprisingly early in the process.
Research:

Charles Goodyear and Vulcanized Rubber
48:22

SYMHC Classics: Penicillin
42:45

Behind the Scenes Minis: Dorothy Everywhere
20:00