I can only hope that people will someday realize that systemd did nothing more than add a userdb field, symmetric to other, similar, userdb fields, while the distro installers are the components that actually decide wherever you need to enter your data, and more importantly, if that includes an actual verification of that data.

If you want to ensure that real age verification will never be a thing, tell your distro maintainers how you feel about that, participate in relevant discussions about the installer etc. Also, support realistic pushes towards keeping it out. No, a random GitHub user won't be able to maintain a hard Ubuntu fork without systemd. Not even for a day. However, it is possible to maintain a soft fork of the installer, minus age input, including the building infrastructure for release images.

Even if systemd would now remove the BD field, or all user info fields, distro maintainers could and would just switch to another implementation, nullifying any efforts and just worsening the situation.