Anything classed as Industrial Perry or Cider on this site refers to the fact that it is produced in a less than natural manner. I dont know how they produce it exactly, I consider the difference to be akin to the difference between fresh fruit juice and fruit-cordial. I expect the main ingredients in these drinks are apple/pear flavoured concentrate, sulphates, industrially produced alcohol, CO2 and water.
In any case they don't really compete in terms of taste and quality with the real thing. But they are cheaper to produce and can be standardised unlike real ciders/perrys, as a result they are far more common.
In recent times the prevalence of the most common sickly industrial ciders like Strongbow and Blackthorn has been challenged by much milder tasting ones such as Magners which are marketed as of being of a higher quality, this is reflected in the price. In reality they're just as crap.
I also find it amusing that they have introduced serving these supposed quality ciders over ice; it's obviously a gimmick but it also tells me that there's something they want to hide. Ice - and coldness in general hides the flavour of drinks; with whisky for example the higher the quality of the whisky the less likely you are to want to drink it over ice. And of course why else are yank beers served so cold if not to hide the fact that you're actually drinking urine. Obviously the makers of these sham quality ciders don't want people to know that they're actually just drinking diluted Strongbow.