Nobody said the holodeck is a zero energy system. It was theorized that it takes less energy to run a holodeck program than to run the replicator multiple times.People have been entertaining themselves just fine for all of human history without having a limitless consequenceless pleasurefield. I'm sure 24th century humans can manage the same.
For most of the show Voyager wasn't low on resources and in those cases it made sense for holodecks to be available. When they were low enough on power to ration food, they can go off.
I don't buy the argument that because holodeck matter is reclaimed it's somehow a zero energy system. First of all, entropy bitchez. Turning energy to matter then reclaiming it is going to have inherent waste. Second of all, running forcefields with fine motor precision and specific textures and manipulating light finely has got to take more energy than just the energy it takes to manifest the matter.
Also it's a little strange the writers never thought of giving the ship the ability to fully repower just by hanging out really near to a star for a little while.
Being able to fully repower themselved by collecting solar energy makes little sense based on how their engine systems work. But in a way ships can, using the Bussar collectors.