Could you tell me more about what you mean by WordPress holding code for ransom? I tried searching but couldn't find much.
I'm not sure why you consider applying this model to be "grandstanding for attention or money", and (re: bus factor) I'm not sure why a team of developers couldn't work this way too.
As for cost...someone who wants to work - and continue working - for the community will obviously want to price their time in a manner satisfactory to the community. Could you give any examples of people charging exorbitant sums using this model?
PS: The "XMPP author" was not actually on XMPP. Also, that author was (as I mentioned) advocating for disallowing commercial use, which - forget about being "congruent" - goes against every definition of "open source" or freedom-respecting software...in contrast, I'm pretty sure the Free Software Definition doesn't say anything about your development or monetization model, as long as the four freedoms of users are respected.