Jazz was inevitable (It was only a matter of changing some rules)

With many things that eventually occur, they may have been slow-cooking in the oven for centuries. It is conceivable that the sound of a C major7 (#11), or a C7 (#9) was always heard by a composer at a keyboard, but the sound was self-censored, but not ignored. Most often it was resolved through melody and counterpoint, as tension-release, up until it was acceptable to keep it unresolved. Now we just hear it, and perhaps ignore it as "jazz".

All inevitabilities in the future will arise in the same way: All rules have a shifting baseline with absolute thresholds: They are flexible up to an acceptable breaking point. Defining "acceptable" is the issue.