> participants need to be competent at writing and reading prose (it’s harder than it sounds) and even with the best of care your ideas can easily be misinterpreted resulting in the loss of an async cycle.

I get what you're saying here, but can't we replace writing and reading with speaking and listening, and claim somewhat the same thing for synchronous communications?

To me, if you have employees who can't write or read effectively, that's as bad as employees who can't speak or listen effectively. If you have those kinds of people, you have hired sub-standard people.