Using your deliver company analogy, the delivery company would not be able to invoice the customer as the goods were not received. In the ISP's case, they still charge regardless, and blame the FNO. Agreed, the FNO is usually to blame, but I agree with OP, we don't actually care, I'm paying the ISP, they must deliver. failure to deliver, then reimburse. else it's easy to keep blaming the FNO, load shedding etc.This is like blaming a delivery company for not delivering a package because your municipality has not been maintaining your roads and it's impossible to get to your house. Sure, you can rant and rave at the delivery company and tell them you pay them and it's not your problem they can't drive to your house, and what are they going to do about it. But at the end of the day there's nothing they can do if they can't get to your house.
Now, having said that, I do agree that there is a lot wrong with the FNO/ISP model we currently have in South Africa and it definitely needs a lot of improvement. However let's just remember it wasn't that long ago that everybody used to say that we would never get fibre in South Africa. It's a small miracle that we do have fibre considering how small the market is in South Africa, and it's an even bigger miracle that most of that network (mostly) manages to stay up during loadshedding.