A dishwasher buys the convenience of not doing the dishes. That frees your time in itself and in general the time it takes the dishwasher to run is not critical.
I have children. They use plates, bowls, cups, cutlery, more bowls, more plates, more cups. I have only limited room for additional dishes. Dishes better be done before dinner or else somebody is going to have bad time. And generally if someone in the family is having bad time then everybody is going to have bad time.
Of course but since there are several hours between meals, even if you have to run your dishwasher after each meal the time it takes to run is not critical as long as it's done within that timeframe.
Basically, in general it does not matter whether it takes 1 hour or 2 hours.
The eco mode of our dishwasher takes 4 hours.