Good points overall, but this: > people with fewer family/community/social/hobby/work obligations, because the more of those obligations one has the less time

Good points overall, but this: > people with fewer family/community/social/hobby/work obligations, because the more of those obligations one has the less time one has for online discussions seems like a bit of a category error. There are any number of stable online groups that should be considered under the rubric of "community/social" activities. People participating in them know and expect things of each other, just as they do in a face-to-face group.