I suppose you are aware that those sales would probably go global. Which they are not currently, because there is a lack of proper regulation and standardization.
They probably don’t have to be as good as real weapons, but obviously with regulation, they’d have to be good enough to be safe to use.
Considering media industry is one of the biggest industries in the world, I’d think the market is more than sufficient to sustain multiple vendors.
“The media industry” is everything from a big-budget science fiction film, which uses no conventional-looking weapons at all, to a local newscast, which also doesn’t.
The number of productions worldwide needing realistic-looking prop weapons is very unlikely going to make any manufacturer justify redesigning their arms or recalibrating their manufacturing equipment, if recalibration is all that is necessary and new equipment wouldn’t also be required.
Prop firearms are not really consumable items. They are just rented over and over again by production companies from rental companies. And when they break, the rental companies would first repair them before buying new ones. They could be decades old and have been repaired over and over.
I assume the shitty reliability of prop guns has more to do with their age and how much they are used rather than low manufacturing quality.