yeah but also with rowgates, like i said it depends on the type of queue, if you got a tailgate (energylandia) or some staff assigned but most queues have that first check in gate, where you only let in the passenger for the next trains and so on. you have your clean train, everyone is supposed to be where they are and you can dispatch fast.
again one example out of real life: one of the last trips i went one day to ploppsaland de panne and the other day to walibi holland.
Ploppsa is fairly small and family oriented park no fast pass, no single rider, one line and just row gates. They have this woodie heidi, a fun family coaster and the chaos at the row gates wasn't funny, firstly like people are many blocked the first two row gates, while the front row was empty, then there were children under the height requirements, backpacks needed to be stored and so on. All in All i didn't exactly clock the dispatches but some took around 3-4 mins.
Next day Walibi Holland, Untamed: At the station gate: the height were checked between dispatches, rows got assigned. On the rowgates: you get your instructions how to board the train, what to do with your article, then you board and the staff has to check your seatbelt and put those have rmc restraints down.
Now dispatch time was around 1-2 mins.
All in all cause it was streamlined: just one group per train and everything important checked before you enter the station.