I'm pretty convinced at this stage that Msft know they don't have much to launch the XSX with, and have known this for quite some time. They are going to hang the near future on GamePass, 3rd party, and BC, knowing full well that they will be able to properly respond to Sony's output in eighteen months to a year.
If this turns out to be the case, there will be questions as to why they didn't delay the launch of the console, but they've obviously number crunched, and decided that they can easily get through this rather lean period, with the promise of much more to come.
Weirdly, this is directly the opposite of two generations ago, when 360 was the better console out of the blocks, and it took Sony quite a while to catch up.
XBox could still have some big news to announce of course, but I wouldn't be surprised if this was just about it for the time being - with GamePass and third party being what keeps the fanbase happy.