semantic versioning wasn't a new concept when semver 1.0.0 was released. Before that lot of projects already followed this scheme and this was just made official so that everyone should follow it as the standard. So its kind of like if all web browsers support non standard features, and then the committee decides to add it to the standard to make it official. My point is, that the release of semver 1.0.0 isn't the invention of it.