It's certainly an interesting question for those who weren't around at the time, or are too young to remember it.
The embryonic stages of digital TV were quite badly handled by the regulator (ITC
) because of very poor planning by the various governments of the 1980s/90s.
The main contenders for the newly developing platforms (DSat, DTT
& to a lesser extent DCab) ended up squabbling like 'rats in a sack', with the result that many companies and their shareholders, lost £Millions in the process.
BSB lost out to Sky because their pockets weren't as deep as "Uncle Rupert's", and couldn't sustain the losses as long. Furthermore, even though BSB had a better quality picture using DMAC, I don't think there was much room for expansion beyond 5 channels on the Marco Polo birds.
ON/ITV Digital had an ultimately flawed business model of poor quality signals, with too many channels on a newly developing transmitter network with too few subscribers. They then made the 'football deal' which also had devastating effects for many clubs when they went bust.
Withholding ITV from the Sky platform probably didn't do them any harm in the short term, as most accessed it through analogue anyway. However, I doubt it had much (if any) effect on the subscriber base for ON/ITV Digital. If anything, it came across as rather petty at the time, IIRC, so not a great PR move.
Of course, in the end, the 'rats in a sack squabble' led us to Freeview.
DE88 and BeanosOnToast gave kudos