Former Navy snipe speaking up - what the OP seems to be describing is a bit of what happened with US Naval weapons systems starting in the mid '80s.
The original US missile systems (the Mk 10, IIRC) on the original guided missile ships had magazines with horizontal storage for the missiles, and a rather large “footprint” for the missile handling equipment. For an example of this mod of launcher consider the USS Long Beach CGN 9.
From here the Navy made at least two competing missile systems that utilized vertical missile storage and loading - the Mk 26 and the Mk 13. The Mk 26 was what we had on my ship, the USS Virginia CGN 38, and was one of the upgrades for the Virginia class over the USS California CGN 36, with their “one-armed bandits.”
All of these traditional missile launchers pulled missiles out of the magazines, put them onto launch rails, then would return to the neutral position, before they could be reloaded for another shot. The problem was that even as late as I was serving on the Virginia, in the early 1990s, misfires still happened. When there were a misfire with a missile on the rail, that rail would then be effectively out of comission. AIUI The reason why the Navy went back to the Mk 26 for the Virginia class was that while the Mk 13 had a shorter reload to firing cycle, in case of a misfire the whole launcher was out of commission, until the misfiring missile could be safed. Which usually took a number of hours, and finicky work, too. Nothing one wanted to do while aircraft were coming in at one’s ship. The Mk 26, in extremis, could continue to operate with one rail occupied with a misfired munition, allowing some continued use from the mount.
Then in the late 70s and early 80s US missile technology got sufficiently advanced that it became feasable to store missiles indefinately in box launchers. The first example of this in the fleet were the Armored Box Launchers that were installed on the Virginia class ships in the early 80s - mainly to give the ships a Tomohawk capability, a missile which couldn’t be used in SM missile mounts, like the Mk 26. Eventually box launchers were installed battleships as well as many of the nuke cruisers. Because of weight and space considerations there wasn’t room for putting them onto Spruance class ships, nor onto the early flights of Ticonderoga (Aegis) ships. But these box launchers were an interim solution, and not well regarded. For the Virginia class ships, they had to sacrifice most of their helo capability to get it, and the launchers themselves were pretty complex.
A plan was made to try to come up with a way for ships to use the same missle system to handle Standard Missiles, ASROCs, and Tomohawks. SM and ASROC weren’t hard - they’d been developed by the Navy, with system compatibility as a goal. Tomohawks were the joker in the deck. I suspect someone thought about the implications of the Exocet anti-ship missile installations that had been put onto many US ships by then and wondered why launch rails were necessary.
That lead, (with much over simplification on my part) to the VLS system that is current for the later flights of Ticonderoga ships, and the Arleigh Burke ships. These are arrays of missiles stored in maintenance free vertical boxes ready for launch. At the time that I was in the Navy the word I’d gotten from some of the Gunner’s Mates was that while a Mk 26 could get a second missile off before a VLS ship could get it’s second missle launched, after that we lost time very, very quickly.
To return to the OP’s question - yes, they do use large box arrays of missiles that are essential impossilbe to reload outside of a port facility. The reason it took so long to set that up, I think is because of the time it took to make the sophisticate missiles that the Navy wanted maintenance free enough to be kept in box launchers that required little or no maintenance, while still being at least, say, 95% reliable.
On preview - I can’t speak to land systems - no experience there. For naval systems the idea of the alpha strike just doesn’t make sense: missile defense is pretty chancy, at best. The best defense is convincing an incoming missile that the ship is over there not here. Against an unarmored ship a single anti-ship missile is capable of delivering a fatal hit. So, why send more than one or two very expensive missiles at your target? If the target survives the first salvo you will hopefully have a chance to fire again at it.
Now, there is at least one officer in the Pentagon who’s been advocating Fire Support Ships which would be essentially unmanned, or very lightly manned, battlewagon sized platforms with up to 8, I think, VLS arrays, that would be able to provide a huge “alpha strike” capability either with Tomohawks for combat support ashore, or with SM to fend off an entire small nation’s air force. The advantages would be both a huge throw weight, as mentioned above - for the initial salvo, or salvoes, and being much cheaper than a CVN, both monetarily and for the potential loss of life. But the loss of the flexibility and sustained engagement capability is very real - and for that reason, I believe the idea never got out of the planning stages.