Nothing can beat a live event

LATE ON A Saturday night at New York’s Madison Square Garden in November, a crowd of more than 20,000 people, including many who have flown in from far-flung places, is buzzing with anticipation. This is the first mixed-martial-arts (MMA) event held in New York state, where the combat sport was outlawed until recently. Fans have paid a total of $17.7m, a record gate for any event at this historic arena.

This evening they have already sat through many lesser bouts. Now Conor McGregor from Ireland, one of the most popular fighters in the Ultimate Fighting Championship, the leading MMA promotion company, walks towards the ring to the cheers of thousands bedecked in Irish green. He is seeking to take the mixed-martial-arts organisation’s lightweight championship belt, held by Eddie Alvarez, to become the holder of title belts in two different weight classes at the same time. Mr Alvarez enters to the sound of boos. In the second round Mr McGregor wallops Mr Alvarez to win by a technical knockout.

Now that is mass entertainment. The night of fights had a great many more viewers than any contest in ancient Rome’s Colosseum. More than 1.3m...