Here are my conclusions for Is there anybody caring about Spanish modules? and Is there anybody caring about German module?
To maintain such locale modules, we need to rely on external maintainers because the code maintainers do not have the required knowledge.
Before inclusion, it is often easy to push the requirements to the same level as the other core modules because the contributor has the incentive to be included.
Once included, this incentive is gone and we must rely only on the goodwill of the external maintainer.
Over time, the requirements for the core modules evolve and we need to push them also to those modules. And this is where the friction starts, the external maintainers may not have the resources or may disagree with the new requirements. This means that only the technical minimum is done to keep them operational.
De-facto those modules become second citizen of the core modules. Indeed this situation is no different than if they were maintained outside the project. This is why I think the new rule should be that locale modules that core maintainer can not maintain should not be included in the core (at least until the external maintainer has shown for a long time (maybe 5 years) the willing to maintain to the core standards).
So this means that the account_es* and account_de* modules will be removed from the coming release.