They had a month to move stuff out and you wouldn't see that because of the tunnels. Besides you wouldn't store weapons inside the hospital but underneath it and even then combining your HQ with a depot full of explosives is a really poor idea.
Fighters were moving in and out of the hospital with what they carried in their chest rigs. No need to store anything there when literally every building in Gaza was available for storage simply by pounding on the door and shoving a gun into the face of who ever opened the door.
Centralized storage is outdated, centralized storage against an enemy who enjoys technological superiority and unhindered surveillance is a really, really bad idea and not how an insurgency operates.
Don't know, frankly.
Could Hamas have moved things away?
Sure. That's a possibility.
But that would be a huge contrast with their overall readiness and will to fight.
Ok, so, one can assume the pre-invasion strikes carried out by the Israeli Air Force and Navy have thinned the herd significantly; such as killing terrorists, destroying fortified positions, stockpiles, infrastructures, etc.
Ok.
Fights still occurred afterward when they invasion took place, with Hamas managing to hit the IDF hard enough to inflict a number of casualties and material losses.
But that was only as a result of the early days of the invasion, back when the IDF was still on the outskirt of Gaza. Inside the strip, but not in the city itself.
One can say Israel has the upper hand when out in the open, they can make the distance play in their favor. But once engaged in urban warfare, their formations of armored vehicles, in relatively narrow streets and surrounded with tall buildings, would have been seen as golden targets.
I mean, nevermind this is about the IDF, invading Gaza and conducting military operations in that environment is nightmare fuel.
Anyway.
Maybe the "disappointing" amount of guns and other devices is due to Hamas spreading things around and evacuating stuff away for later use.
Maybe the "big caches" haven't been found yet.
But another possibility could be that Hamas logistics and supplies were exaggerated.
For an organization so dedicated to the destruction of Israel, Hamas sure isn't playing the part in a very convincing way.
Which isn't necessarily a bad thing, mind you.
If Hamas' subpar performances are due to the fact their fighting spirit and capabilities got overestimated: good.
If they are due to their capabilities and such having been smashed by the IDF strikes: good as well.
But in the first case, it could backfire pretty strongly and negatively against Israel.