I personally think this will be a spectacular fail for various reasons.
1: Ease. Most people have sky now. Yes its a change and people don't like it but you have now made it complicated as people have to sit in front of a PC screen when previously, they just changed the channel while curled up on the couch.
2: If my Dad was knocking around, would he know how to stream on the internet? Basically you have wiped out a demographic above the age of about 55. I know what I am doing but that's cause I have moved with the times. I put myself in the minority.
3: Do I want to watch this on a 4' or 10' screen as opposed to my 44'? Yeah I can jack it up to my TV but can I actually be bothered when my sky box does it already?
4: MySky. Can you watch the game in 2x stream on the internet and fast forward through the HT break? End of.
5: This works on the assumptions that the quality of feed is good and that there is no data cap on it.
6: For the younger folk of today that are tech savvy and have all these fancy idevices, do most of them have $150, $250 that they are just going to part with when they will find other ways to find it anyway? Justin.tv?
7: My son got up and watched Spain 82 when he was a little tacker at the wee hours of the morning. Explain to me how you are all going to crowd around the small screen as a family (and if you stream it across multiple devices then its double the bandwidth usage).
8: If you don't have a PC or don't have internet, what do you do then? You might be surprised at the amount of people (and again I am looking at the 55+ demo) that do not have the internet.
9: So TVNZ have 1 game. Do I really want to watch Stoke vs Reading (or whoever?)
This country is not advanced enough yet nor does it have the population model to be able to support it. Take 50k subscribers at $150. I am sure the rights cost more than $750k a year and that does not include the backend costs.... (EDIT: My maths is actually quite shocking so please disregard this point. $7.5m)
Call me a pessimist but I just do not see it working in any sense.