almost all FOSS work is async. any company that has teams across multiple timezones does async work.
for me, unless we are doing pair programming, i expect communication to be async, even if we are in the same office. you don't get to interrupt on demand, but you better wait until i am mot focused on something else, and respond to your message
I have found FOSS to really illustrate the problems of async work. It’s extremely difficult to break in as a new contributor. There is no help like in a corporate job, you can post on GitHub and hope someone gets back to you at some point, but no one is going to get on a call with you and walk through a problem or the context.
Which shows in the contributor stats where 1-3 people do all the real work and everyone else submits trivial patches.