I respectfully disagree
I respectfully disagree with your analysis. It's impossible for anybody to say for certain what would have happened to OnDigital had its encryption system not been hacked.
OnDigital carried most of the best channels available on Sky, and was much cheaper. It was also possible to receive if you were unable to have a Satellite dish, as applied to a great many people. People in rented accommodation, or in flats, or listed buildings, or students, or people who simply moved about a lot (you could take your box anywhere). Look at the success of Freeview today - it is essentially the same technology. It is successful not only because it's free, but because it's also much more convenient than Sky.
If the hacking of their smart cards had no effect on the success or failure of OnDigital, why did somebody clearly spend a great deal of time and money doing so? And in any case, should they be excused simply because some people feel that OnDigital was already badly run?