Progression happens when people push the current paradigm causing a shift, or a schism in the model. This applies to bicycles as well. From the era of the klunker and the cruiser influencing mountain bikes to people riding 23mm road tires on gravel roads. Hell, I think it’s safe to say that our generation has seen various permutations unfold from people who push their bikes just a little more than others. To the verge, even.