Maybe I should have said Caspa, rather than TiVo... Sky is the only serious player in the paid TV market. This is a monopoly. This is bad for consumers. Caspa is making a start by competing with Sky's pay-per-view business. Even if the Caspa service is a major success we still only have a two players in the paid TV market. This is a duopoly. This is also bad for consumers as we have seen in the mobile market.
We need more consumer choice in the paid TV market.
Pay TV is ridiculously expensive to get involved in - Sky took a serious risk in even setting up in the first place (but it did pay off). Can you blame other providers for not wanting to get into that business?
Also, it's an oligopoly not a duopoly - have you forgotten TelstraClear cable with its pay TV offering? (Even if they appear to only rebroadcast Sky content - but they do so much cheaper!)