Where's the proof that Live TV is going away anytime soon or that the numbers are dropping rapidly. There is still an extremely large number of people still subscribing and those that are cutting the cord are an extreme minority at this point in time. Nothing points that cord cutters are going to be a major factor before the life of the Xbox One will be over.
It's not about the overlay, but the integration. The overlay is a perk, the integration is a better perk. It's how you'll move between the two and always be on the Xbox because being on the Xbox makes it easier to deal with everything. DirecTV, and I'm a huge fan, is kinda shitty in its overlay. It's nice, but there is so much more room for improvement in just responsiveness alone.
People are putting too much emphasis on the TV aspect and it's kinda dumb how much weight people are putting on it. It's one piece of the puzzle. You can still play games, you can still stream from Netflix, Hulu, Amazon, HBO, ESPN, and a number of other sources, AND you can use Live TV from Cable, Satellite, and so forth. If you're a cord cutter, you don't have to use it and can use the cord cutting services that MS also supplies. If you have Live TV, you can also participate. Why are options and covering all bases a bad thing here?