Also, holodecks are limited in number. Voyager had two, and during one episode where the plot point was that they were in an area of space with literally nothing, the holodecks were in such high demand they had to schedule time there so everybody got a bit each. With Voyager having 150~ people onboard, I can easily imagine that sucking. The Enterprise had more holodecks (4-6~?), but with around 1000 people onboard, if they were in the same situation of there being nothing to do, the Holodecks would probably have been equally crowded.