Sorry but you are incorrect & have been fooled by BT's clever marketing department, you can paint stripes on a Donkey & call it a Zebra but it's still a Donkey underneath. BT have no physical way of getting the broadband to your home without Openreach for which they have to pay line rental, they just don't provide you with a phone number.
The reason why this was not possible before was the whole BT system was designed around the phone number premises link, not circuit number premises link.
And this is true of other providers such as Sky, Virgin etc. They all use openreach infrastructure to get the broadband to your house.