With the current system the individual is still in control of how long something takes. A wise old driver told me many years ago (Reading still had mk1 metrobuses) to never make eye contact with anyone who isn't on the bus. The moment you make eye contact with somebody running for the bus they stop running and take there time as they now hold you to ransom! I would normally wait for runners if the frequency is 15 minutes or less, but if there was no talking once on, they wouldn't get much more out of me. Bus Drivers eh?
It doesn't matter how long you wait. Someone will always appear around the corner as you close the door.
On the subject of conductors, Blackpool trams have them. There are usually two and at busy times three or more. They take cash for fares, although off-tram fares are available at a discount. The trams hold 200 passengers and have many doors, and you can generally set your watch by them. They run at a profit - Blackpool's transport company is owned by the Council, and hands £1 million to the town's coffers each year, much of which is generated by the modern light rail system.
This isn't something in favour of trams, but in favour of conductors on high volume routes. But possibly the best way I have seen of taking fares is in London, with contactless cards. There is no reason that could not be taken forward in Bristol for one, and possibly a few other big conurbations too.
