One of the most important value drivers in e-business is the lock-in effect of ecosystems. BC means you lose your whole digital library when you switch to a competitor. The switching costs increase as a result.
It's also guaranteed that the Xbox will have BC. If Sony doesn't have one, there will be a huge backlash. Sony won't want that at the start of the gen.
The PS5 is guaranteed to have BC.
Yeah, it really seems like a major slip up if there is no BC. You think anyone is that dumb enough not to do it? That's what worries me sometimes... lol