The whole point of BC is to lock people into your ecosystem. People who weren't 360 gamers last gen won't care really about BC if they buy an XBO. It's for the 360 gamers to see value in upgrading within the same company. When a company considers having BC in their next console, it is for the purpose of keeping people locked in and not wanting to jump ship. By not having even a strategy laid out for BC meant that MS didn't think they needed anything at all to keep people from jumping ship to PS4. That was obviously flawed thinking.
This. There's no way Apple would be able to convince people to keep upgrading iPads if the latest one wasn't backwards compatible with the entire history of App Store software.