I generally agree with you and the "short" format is what makes it successful, but Melvyn said himself that they choose teaching professors because they would know how to explain subject clearly and after almost two decades of listening I'd say it has mostly worked.
> they choose teaching professors because they would know how to explain subject clearly
Hmm! The majority of academics in the UK teach... most of them reluctantly and badly because it's mandatory for their research contract!
Those that revel in it are used to monologuing extemporanously for hours every day in the lecture hall and supervision without interuption. It's quite far from a snappy conversational media performer.