The issue with comes from a line in Caretaker which went something along the lines off "We only have 38 torpedoes and no way to replace them" so one can infer that they didn't have any such equipment onboard to replace them or they contained elements which couldn't be replicated, which would mean something more complex like a shuttle should also be beyond them.
And it's pretty obvious in the context why this should be: the ship is broken. I really don't feel the need for an extra line to reiterate that.
The only other ship to have suffered from a shortage of torpedoes in the history of Star Trek was the
Defiant, being "down to" 45 at one point of "WYLB". Possibly she didn't have the onboard equipment to create more - but just as probably, ships in the heat of combat don't replicate torps to meet the needs of the hour, and the tactically smart thing to do is to go for centralized resupply from replicators elsewhere. We do know torp warheads are a non-triviality, deemed worth stealing in "Tribunal", but we never get indication that they would be unreplicable as such (the Maquis had access to replicators and still could be framed for the theft, so replicators aren't a trivial solution - which already covers all the bases and allows them to be a solution in the right circumstances anyway).
I'm of the mind that quantum torpedoes require special launchers. In "First Contact" (the movie), even though they were facing Borg, most of the ships were still using photons. And the quantum ones were obviously bigger and more potent. Were they interchangeable, the whole fleet would have been packing quantums.
The weird thing is that quantums never really were more potent. Here,
four of them are fired to destroy a small and unshielded target - single photons have dealt with larger unshielded structures before. In "Defiant", volleys merely hurt and disabled Cardassian ships, rather than blowing chunks off them. Photons
can be fired in volleys that do little damage (to shielded targets), too, so there really isn't any telling. Adjustable yield warheads and all that. In the end, though, quantums have failed to demonstrate superior yield.
Where they appear to excel is killing proximal targets without danger to the firing vessel herself. It's probably really nice to have the option of using torps at close ranges, in addition to phasers, even if those aren't super-duper-strong torps.
And remember what the Defiant's pulse phasers did to Jem'Hadar fighters. One burst, and they were space pollution. If Voyager was intended for serious combat, it would certainly have had them, at least in its forward array.
Anybody can make space dust out of Jemmie battlebugs. Keogh just wouldn't have chosen to, in the first encounter.
Klingon BoPs fire spray-and-pray pulses, too, and kill bugs with a single burst. But sustained Starfleet beams kill BoPs equally easily. And beams carve up
Excelsiors, but pulse volleys don't even char them. There's no consistent superiority for either mode of death ray application.
Pulses would be great against the Borg if the key to victory is varying some parameter in the beam. Perhaps the hardware doesn't bend to ramping the parameter up and down, and works better by turning off for the duration of the adjustment? Or then a hail of differently set pulses is more effective than a ramping beam in surprising the Borg. But clearly "varying of parameter" is no good in standard combat against standard opponents, because it is not standard procedure, either as regards death rays or as regards shields. Intuitive enough: fidgeting detracts from doing.
Timo Saloniemi