The whole alpha/beta naming scheme is an obsolete relic from a different era. An era where all of the features were made in one monolithic group for release on physical media. The features were made first for alpha, and the bugs were fixed afterwards (in subsequent betas, release candidate, whatever).
In this era, new features were only added in a new major version, which will come years later, after their own monolithic testing and release cycles.
For many systems (such as web apps, web delivery, automatic updates/patches, internal corporate apps) it just doesn’t need to be done that way anymore. There’s no reason other than tradition to hold on to arbitrary forty-year-old labels like alpha and beta. I’ve stopped using them years ago, and I haven’t missed them once.