The cable TV market in the US works very differently to the UK. In the US you can "bring your own" cable box, you buy a
CableCard from the cable company and plug it into your own box.
Obviously there's still some cost to Virgin Media but there is with any box they provide, we'll still end up paying some sort of fee to get the TiVo hardware but it won't be hundreds of pounds.
TiVo provide all of the EPG and back end services, there will still be a monthly cost for this, whether VM include it in the XL package and others pay a couple of quid a month is yet to be seen!