Regarding stability it looks like not every container based on Jakarta EE also works that well with MP Config:
Of course Mike knows better than anyone else, that Eclipse Foundation often saw more than one project accepted with exactly the same goal:
So there would be nothing wrong if enough people (either from the old JSR or different projects dealind with configuration) gathered around a Jakarta spec that could be a "fork" of mp-config or something "inspired" by it and others. Of course using a working piece of code can't hurt, but claiming "MP is the only place where innovation happens" while no significant commit is seen on Github over the past 6 months denies reality compared to several others like Helidon:
https://github.com/oracle/helidon/graphs/contributors I won't even mention Spring and Spring Boot because their adoption and ecosystem around them is undeniable.
Speaking of Dropwizard, while it was already stable and mature before the idea of MicroProfile even came up, a kind of subset from Dropwizard Config
https://github.com/joschi/JadConfig is also a notable example for an annotation based approach.