This is the correct response IMHO. It's a social problem and all this yakking about tools and web interfaces versus email must be coming from armchair experts who have never tried to be a maintainer.

I encourage them to try it and learn what the real difficulties are. More maintainers are needed almost everywhere, just choose a project and dive in. And please, remember your health and the real world too! They will be easy to forget.

Lowering the cost of entry for contributors is no longer a problem. I doubt it was ever a problem.

I also doubt computers have changed the organizational problems very much. The same complaints (with some translation) could be made for any nonprofit, and many businesses too.