It's a matter of business model. If you're going to sell hardware at cost, then you absolutely need to make revenue somewhere else. If you generate significant revenue from the hardware however, the subscription is just gouging. TiVo hasn't taken off because of their business model. Their marketshare is still crap and is likely to always remain crap.

I don't pretend to know how TiVo blows through its income, I'm only making educated guesses on why they're not everywhere.