Or it could just be a case that holodecks were never meant to run an entire starship. The incapability is unlikely to be the actual type of power used, since holodecks appear to run off the same EPS as other systems on the ship, but it could be with distribution, stability, and even regulation. You can send power to the holodeck from the warp core, but getting the holodeck to power the warp core could be asking for it.
I doubt it's that easy, otherwise it would be standard practice. And trying to feed 150 or so people three times a day might be considered an unnecessary drain on the ship's power grid when rationing and scrounging are other alternatives that can allow the ship to go longer without searching to refuel the main tank.
That's why replicator rations were introduced and soon became the basis of the ship's economy, along with holodeck time. People were probably issued X number of rations per month and could use them on whatever - favorite food, a Hawaiian shirt to wear on the holodeck, or when Harry replicated a clarinet to replace the one he forgot back on Earth.
But once those rations are used up, you either had to persuade someone else to spend theirs on you, trade something, or get used to the leola root stew.
Rank would have had its privileges, of course, but Sam Wildman's allowance would have been upped once Naomi was born.
I remember an early episode where Paris cleaned up on rations when he started a betting pool on whatever. Janeway shut it down, but must have changed her mind at some point as she later put down a bet on when B'Elanna's baby would be born.
It wasn't used all the time. Despite the number of holodeck episodes in VOY, its usage was probably regulated more than on other ships for that reason. Outside of special circumstances and unauthorized access, crewmembers probably had to get permission (off-screen, of course) rather than use it whenever they wanted.
There are scenes of people swapping shifts and trading favors for holodeck time, so unless it's one of the "open door" times like Fairhaven when Janeway allowed the crew to go there whenever they were off-duty and felt like it, then I would imagine holodeck time was rationed as well.
Paris did well to create scenarios where the crew could go to relax and have a drink, shoot a game of pool, and so on. Given how far they were from Federation space and known worlds and starbases, it's not like they had as many opportunities for recreational shore leave. The holodecks on Voyager were necessary for their mental health, and also served as a way to set up training facilities.
