I take it the OP doesn't remember the Bellew vs Cleverley rematch PPV? A non-title 12 rounder between two domestic level fighters who both, two fights previous, had been completely mullered at proper world level (Adonis Stevenson & Kovalev doing the job, respectively). Staged mouth-offs & choreographed shoving, a bit of "Oh, this one's personal" from the UK press, et voila.
Joshua has so much name recognition in the UK that IIRC his fight with Eric bloody Molina was on PPV, so of course Fast Eddie wasn't going to put a unification fight (as laughable as this fight's status is) on regular cable.
PPV in general, of course, is mostly a piss-take.