While overall I agree with your points, the reason I think they might settle with a smaller constellation is that they could sell it as an AWS service with dire

While overall I agree with your points, the reason I think they might settle with a smaller constellation is that they could sell it as an AWS service with direct integration with their data centers. For example, as a lower latency low bandwidth interlink between continents. It would be similar to how Starlink integrates with the networking at Google datacenters, but made explicit as an AWS service.