Semver also allows you to make breaking changes at anytime with the bump from one major version to the next — e.g. if you look at something like RxJava they use

Semver also allows you to make breaking changes at anytime with the bump from one major version to the next — e.g. if you look at something like RxJava they use semver well in this way & don't shy away from breaking changes to deprecate and tidy the API. If anything I think perpetual v0 dilutes the concept as gets people used to projects being stable at v0 rather than considering them alpha