This notion that a new Tomb Raider won't sell due to a relatively small install base, or will fail to noticeably move systems, or that S-E or CD will feel the wrath of spurned gamers and be held responsible and crucified, is beyond ridiculous, like much of this thread.
It's still one of the most famed IPs in gaming. It may have faded since its heyday, and whether MS considers it worth whatever they spent for the privilege to host it is on them, but the immense iconography Tomb Raider boasts is going to absolutely going to count for something, even if it only amounts to a purchase incentive on Bone's part.
Meanwhile, we have a Bloodborne thread with people un-ironically saying that a new IP (fantastic as it looks) is going to help shift millions of consoles.
There are fewer flights of fancy more fanciful than the passions of zealous console warriors. This is exactly the kind of thing MS needs to do to catch up, and you can expect more of it until they do.