We already have access to a Netflix-type service in NZ - actually, it is Netflix! With a proliferation of content channels and ways of accessing it, including directly from offshore, they won't be able to sustain an iron grip through control of distribution channels and "exclusive" distribution deals.
Their distribution channel already has more holes than a colander, and that's only going to get worse. Plus, exclusive NZ rights will mean less and less as the ability to control the exclusivity slips, and it is easier and easier for people to bypass them (e.g., Netflix, Amazon, iTunes and whatever comes along tomorrow).
They will be like the movie theatres who had a cozy little monopoly as the only conduit that films could reach the public, and who abused their customer base egregiously (crappy dilapidated venues, high prices, 6-12 month delays to screen blockbusters, awful overprices snacks). Then technology and market change landed a series of sledgehammer blows that demolished their little rort (VHS rentals, VHS sales, DVD rental/sales at higher quality, parallel importing from Amazon etc allowed, blu ray rental/sales at even higher quality, torrents, Netflix.....).
Now they more or less have to play nice (even more when the last parallel importing restrictions finally lift shortly), and can't survive unless they offer a good experience (good venue, timely release....).
Give it a couple of years, Sky faces the same challenges, and its market power is slowly slipping through its fingers.
TVNZ/TV3 have the same issues - the profitability and value of free to air broadcasters has tanked in the last decade. Ironically, in significant measure, because Sky stole their audience base. Now, other parties are starting to nibble at Sky's lunch.