You can accomplish a lot if you work a lot in a short amount of time. You can probably also accomplish the same amount if you spread that out over a bit longer period of time.
Or to put it another way, you can accomplish a lot with less people but they have to work really hard. And you can accomplish the same amount with more people and they would be working comfortably hard.
The question is, which way do you prefer to work on a regular basis?