The chances of there being no TiVo service are quite minimal; Microsoft's Ultimate TV is still supported long after they're no longer available.
My generic advice for anyone complaining of the commitment, especially someone who's been a DirecTV subscriber for more than a few years, is to worry about it when such time rolls around you want to cancel.
The commitment might be over by then.
The penalty is prorated for the remaining months so it might not really be a whole lot of money.
The penalty can and is often waived for various reasons, including one being "I'm moving and can't have a dish or don't have a proper view of the sky where I'm moving to."
Some states preclude charging such a penalty fee by law, so that part of the agreement is void in those states.
You can suspend your account for up to 9 months; some people have reported their commitment clock keeps ticking during the suspension, but even if it didn't you can delay dealing with a penalty while you check out other services at such point you decide DirecTV doesn't have what you want. There's every chance you'll find that the alternatives are worse and want to come back.
In the "squeaky wheel" category you might be able to complain enough at the time you cancel to have them waive any penalty anyway.
