Plugs (true plugs) require presses that exert many tons of force for good period of time and the ropes require a spinning machine for any kind of production, of course ropes have been made for centuries by hand. I’m in no way an expert though?
It's not the pressure itself, it's a combination of
pressure - which as far as I recall from a vid C&D they have an industrial press which undoubtedly can exert more pressure than SG/G&H old hand-cranked presses (they don't use these anymore) - with
casing (which C&D is not using much at all of) and
steam (steam presses as far as I know are only owned by European companies like SG/G&H, STG and MacBaren, K&K and Dan Tobacco). Also rope machines are only owned by Gawith, the other companies above do not make actual ropes, they make rolls which are then cut (except from Peter Heinrich's Curly Block). Only Gawith has the machines and staff with knowhow to produce ropes at a large scale of any sort.