Maybe it boils down to async being hard and Mutt actually using synchronous network transfers, obliviously assuming they would be zero-cost which they are obvio

Maybe it boils down to async being hard and Mutt actually using synchronous network transfers, obliviously assuming they would be zero-cost which they are obviously not. There's also this work in configuration that you have to do to shoehorn Gmail's labels into Mutt's mailboxes. Oh, have I mentioned already that your 100K+ messages in one maildir will be really, really taxing on your filesystem? I don't know, maybe someone should come and try and reinvent this whole crap around more modern workflows.