Jez, great article. I think I agree with 100% of what you wrote here.
Having said that, and while personally think going cross-platform without waiting to see how the exclusives launching in 2024 affects customer attitudes toward Xbox and MS would be a strategic mistake, if MS does start selling cross-platform, I think it can be done in a way that boosts Xbox.
1. Timed exclusives, if set for a long time period, minimum of a year, 2-3 years being better, could open PS players up to franchises they may not otherwise experience. This becomes especially important in an era of franchises and ecosystem lock-in, where players lose any reason to switch to another console. Exposure to franchises outside their traditional ecosystem can steer customers to the platform that provide earlier access. In fact, that maybe the only good way to break through that lock-in.
This has no short-term impact, but if planning for multiple generations of console success, this could be a good strategy even for the Xbox console.
2. MS and Xbox gain goodwill for being more open than Sony with respect to exclusive releases. This goodwill has some value. It may not be large among customers directly, but in the media, I think this helps make MS the "good guy" in the space (or at least harder to paint them as the bad guy). If it can be done in a way that doesn't hurt the business otherwise (see #1 above), then this added media benefit might make a difference over time.
3. As a partial alternative, if they are committed to gaming over the Xbox hardware, they could announce that they're making all of their games available across all major platforms via Game Pass. Make a big public statement that they are ending exclusives, provided, of course, that hardware makers and app stores allow their games via Game Pass. This would put some pressure (not sure how much, maybe not much at all) on Sony, Nintendo, Apple, and Google to allow Game Pass on their respective consoles and app stores.