I think that the Kodak 126 camera and film format did more to popularise amateur photography/ snapshot photography than anything else at the time.

I think it also make Kodak the dominant player worldwide. It was a case of Kodak leading the way and others followed.(remember Agfa tried their rapid system to counteract Kodak 126 but the Agfa Rapid failed to take off even though it remained in production for many a year)

Kodak C22 and later C41 would dominate the processing world while Agfa and others would have to change from their CNS (CN17) process to C41 in the late 1970's.