In France we did a huge week long festival in Bourges three years running. About 150 bands over the week in approx 50 venues.
The venue we played wanted six, 20 min sets with a short break in between each.
The owner wanted, punter in, buy a couple of drinks, punter out, next one in. He told us, last thing he wanted was someone sitting there with an empty glass for two hours listening to the band.
One corporate gig I did (trio, in a huge chateau reception area) was to play whilst guests were arriving. Played for 30 mins (6 numbers) Got 400€ each and not one person even looked at us let alone listened🤣