They also had like a thousand people on board so they had musicians and actors and all that. Voyager had 150ish people. Perhaps not many of them wanted to perform or watch a performanceIt is only because the show says it is. Even the Enterprise, with it's non-rationed holodeck use still had the crew going to or performing in plays and music recitals. They played sports and games, socialized in Ten Forward...it's not hard to pass the time without using holograms.