The expected release price for the Xbox One X is $499 for November in 2017. While some might argue that the price for the Xbox One X is out outrageous the fact that its backwards compatibility with older Xbox games from previous generations is something that would definitely make people want to buy the console itself. Especially, considering the fact that Sony is not too big on backwards compatibility regarding their game consoles such as the PS4.
In some ways making the Xbox One X backwards compatible with older games from previous Xbox console makes console itself more appealing in the eyes of gamers. However, if people decide to stick with the Xbox One which is also backwards compatible it could potentially hurt the overall sales of the Xbox One X along with brand new titles which would be exclusive for that console in particular.