Ground #3 > It is easy to debunk because Activision games are already on at least 3 Cloud gaming services, including Boosteroid.
Ground #2 > I'm not 100% sure but if I remember correctly, is incorrect, and the CMA mentioned taking that into account in their final decision.
Ground #4 > It's a hypothetical scenario that the CMA did not even entertain. Microsoft's Cloud gaming share of 70% is enough for the CMA to block the acquisition -- even if MS does not intend to make those games exclusive.
Microsoft's only way out of this is if they are able to prove a mathematical error in the CMA's Cloud gaming market share calculation. Otherwise, it's kaput. Interestingly, Microsoft did not raise any objections when the CMA calculated xCloud's 70% market share.