But in the exchange from "Flashback" (VGR) that video keeps flogging, it is explicitly stated that "early stages" of the technology in question did exist at the time, and this is borne out by ENT as well.here's how discovery adds to star trek lore
In "Unexpected" (ENT), Tucker outright says he has experienced 3-D visual simulators before, just not ones which conveyed all the minute sensory details of "actually being there...smell[ing] the ocean, feel[ing] the salt air on your skin," echoing Riker's comments in "Encounter At Farpoint" (TNG) ("I didn't believe these simulations could be this real") and Picard's in "The Big Goodbye" (TNG) ("sounds, smells...the sense of reality was absolutely incredible"), where Troi also makes clear that theirs is an "upgrade" rather than a completely new device altogether. "Sleeping Dogs" (ENT) and "Harbinger" (ENT) show portable holo-emitters routinely utilized by both Starfleet and the MACOs for target practice. And the Vulcans had them as far back as Surak's time, because that's exactly what the titular relic in "Kir'Shara" (ENT) turned out to be! (Kirk's Enterprise herself even sported an impressive holographic recreation room in "The Practical Joker" [TAS].)
In "Dead Stop" (ENT), Trip marvels at a "molecular synthesizer" that T'Pol characterizes as "similar to a protein resequencer"—a device already in use by Starfleet that "can replicate certain foods," yet cannot fully replace a galley and chef, which Discovery too still carries per the "Calypso" short—"but far more advanced." She likens it to one she has seen on a Tarkalean ship that "was capable of replicating almost any inanimate object."
If Harry Kim indeed took Starfleet history at the Academy as he says, then he knows fully well that the "holodecks" and "replicators" of his century represent highly sophisticated and refined versions of tech that has been around for centuries under other names—the smartphones to previous ages' mobile field telephones and cellphones—and as "an expert in holo-technology" per "Message In A Bottle" (VGR), who "used to be nuts about those holo-stories when [he] was a kid" per "Once Upon A Time" (VGR), who "can't imagine just watching the story and not being a part of it" per "Future's End" (VGR), and has even "inadvertently undergone the process of matter conversion" by a malfunctioning holodeck and lived to tell the tale in "Heroes And Demons" (VGR), he'd no doubt appreciate the nuances of the difference all the more. (Not that Wesley's puddle in "Farpoint" or the snowball Picard takes to the face in "Angel One" [TNG] strike as exactly subtle, of course.) Proper holodecks are not mere holographic illusions, but as Janeway describes them, "an outgrowth of transporter technology, changing energy into matter and back again every time a program is run." (Or as Data puts it to Riker, "much of it is real, Sir.") Proper replicators are evidently much the same, and with careful adjustment can even be turned into transporters per "Visionary" (DS9).
As for Voyager's situation, "Basics, Part I" (VGR) pithily sums it up for us...
TORRES: With all due respect, Doctor, we can't even figure out how to project you into this room. How are we supposed to create holographic ships in space?
EMH: [on monitor] I would humbly submit that my program is far more sophisticated than your run of the mill hologram. In fact, projecting the illusion of a large, three-dimensional object has been a trick of magicians for centuries.
PARIS: [facetiously] We'll just do it with mirrors.
EMH: Mister Paris' predictable attempts at humor notwithstanding, that is precisely what I would suggest. Installing holo-emitters along the hull with parabolic mirrors to enlarge the images as they are reflected into space.
KIM: We're going to use up a lot of our power reserves trying to pull it off.
EMH: [on monitor] I would humbly submit that my program is far more sophisticated than your run of the mill hologram. In fact, projecting the illusion of a large, three-dimensional object has been a trick of magicians for centuries.
PARIS: [facetiously] We'll just do it with mirrors.
EMH: Mister Paris' predictable attempts at humor notwithstanding, that is precisely what I would suggest. Installing holo-emitters along the hull with parabolic mirrors to enlarge the images as they are reflected into space.
KIM: We're going to use up a lot of our power reserves trying to pull it off.
They could well have had holo-displays (as did the Enterprise-D, though they were only seen in use a handful of times early in its run) and holo-communicators that wouldn't have been able to sustain the load of the Doctor's program (nor even run of the mill holodeck characters, in accordance with "Persistence Of Vision" [VGR], or solid projections like the latest model O'Brien installed on the Defiant in "For The Uniform" [DS9]), and simply avoided using them for the same reason they rationed holodeck and replicator use: they were chronically short on power.
As for "ship's stores," the Enterprise-D had those too, and "Data's Day" (TNG) shows them to consist of a room full of replicators with more versatile programming than those in crew quarters, where people would go for specialty items beyond the standard fare. That those on Kirk's Enterprise may well have similarly consisted of dedicated matter synthesizers is indicated in "Patterns Of Force" (TOS), where Kirk requests a very specific Nazi uniform for McCoy to beam down in, with its pattern to be retrieved on demand from the computer's historical databases, and mere moments later he materializes in it before he's even finished putting it on, complaining about how the computer made the boots too tight. Or did you imagine this "wardrobe section" was just a bunch of Edoans who were really quick at sewing?
-MMoM

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