I think Oli is getting at dustbags being a step forward in terms of ease of use and hygiene. Then with the arrival of bagless vacuums, a step backwards and return to "dust clouds", similar to the effect of taking a carpet outside and sweeping/beating it.
Am I right, Oli? Correct me if I'm wrong
Incidentally, with regards to your "Not quite an impartial view" comment, he may not be completely impartial but he didn't say anything that wasn't true.