There seems to be a fundamental disconnect here, where folks seem to think Steve and I want everyone to start using the rolling releases. We don’t - we only want folks that are thoroughly dissatisfied with the slower full release cadence to use them.
Users in that position aren’t going to be deterred by the beta label, or the fact that alphas & betas potentially become intermingled: they’ll only be deterred by a genuinely bad developer experience on the rolling release stream (which the PEP aims to avoid).
If folks with the expectation “this is exactly like using one of the stable releases” were to start using the rolling release stream, that would be a communication failure, rather than a success.
The real test of suitability would probably be that first mid-stream alpha release, where the ABI gets changed, and at least some third party packages need to be rebuilt due to segfaults. If folks get bitten by that, I assume at least some of them would say “This is not for me” and go back to the stable release series. But a lot would say “This is what I signed up for”, install whatever library updates were needed, and continue on.
Globally, my guess is that the latter group would number somewhere in the thousands (somewhere between 0.1% and 1% of our user numbers), which should be sufficient for more robust pre-release feedback. It wouldn’t be the millions that use the stable releases, but that’s a large part of the point: encouraging a larger group of self-selected early adopters to contribute to improving API designs before we lock them down in a stable release for the rest of our multiple-orders-of-magnitude larger overall user community.