rollers are almost only used for the printing of fabric bolts; for every new colour an entirely new roller has to be like laser cut etc etc for the design, it couldnt be a more cost-ineffiecnt method of production.
screen printing 500 items with six differnt colours, likewise, would be rediculously labour intensive, as every colour is a new screen so thats like 3000 individual runs! and if uv eva screen printed you know theres no fucking way any one would be bothered. thus, digital printing, for a medium size production would be by far the most cost effective.
ignore the arrogant tone, its just a deception of this psudo-communication.