Cost is a difficulty.
You can't say it's too hard and then when countered by a statement that it isn't then try and hang up on a partial aspect.
At the end of the day, it's neither technically or monetarily difficult to do what OP wants at a basic level.
Extra additions to flesh out such things? Sure, they will cost resources. But at a base level it is not difficult in any way.
Lets explore actually reading.
OP isn't dead set on every single scene must cater to players specific weapons. Just that scenes where a weapon is forced upon them, it is narratively coherent as to why that is the case.
In the case of The Heist. It makes no sense to be locked to only the pistol (Nor does it make sense for you to stash a pistol in that compartment when exiting the vehicle if you are not currently equipped with that pistol - Ignoring the fact that Jackie still brings his La Chingona Doradas with him throughout the mission making the entire narrative decision of not bringing your weapons redundant).
Why couldn't V use one of the AR/SMG's they looted from one of the guards? Or the knife they can throw and magically teleport back to their hand obtained from Saburo? Or given they just got back into the vehicle where they stashed their weapons... Use their weapons? Or better yet... Delamain's Combat Mode actually doing something and using the mounted missile launcher that is integrated into the vehicle?
Yet later in the same mission, when V's in the car with Takemura, it makes sense to not have any weapons. It makes sense you only have the single pistol Takemura gives you. It makes sense your quickhacks won't function. Since the narrative is he's just pulled your ex-corpse out of the garbage and hands you a pistol.
Would it be nice for people like OP to be able to use their melee weapons in their melee builds for these scenes? Sure. But that's not necessary for the basic narrative coherency. That's just gravy that developers can add in if they have the resources and inclination to do so.
Though, there's also the secondary point where these sort of scripted scenes aren't particularly important to the narrative in the first place. Shooting down the drones is irrelevant to the story... So why include it in the first place?
Why not just have Delamain drive through some back alleys and lose the drones or send out some hack that disrupts their target lock or something?
Why have V shoot at some completely janky Arasaka ninjas? Why not simply have Takemura drive, try to evade them and crash while V fights to maintain consciousness? (You know, like what happens to a couple of the bikers including the one that jumps onto the car which you can't do anything to even if shooting anyway?)
This is one of my personal gripes about these scenes. They're entirely unecessary in the first place. Let alone the fact that they are then poorly done with a scripted weapon and lack of build inclusion besides whatever Pistol perks you have.
It's actually less costly (Both monetarily and technically) to not add in these poorly done, unncessary "Interactive" scenes than it is to simply make a non-interactive (Or less interactive in the case that you can still look around and/or have a couple of dialogue options) scene that doesn't create narrative inconsistency between gameplay and these story points.
