Why is SpaceX deploying Starlink satellites without inter-satellite communication capability?

Without the mesh network SpaceX cannot provide global service as originally assumed. A potential (but unsourced) model for what they have is similar to terrestrial mobile internet with ground stations in locations that have good internet access and provide service to a catchment area that reliably has satellites with line of sight to the ground station and the user. A random search got suggesting 2.93% of the US population without broadband access giving at least 9 million potential customers , plus an unknown number who have on paper access but their local provider is failing to deliver/overcharging. While the potential customers are global the current website (June 2020) suggests initial service to US and Canada.

Assuming the Starlink phased array antenna operates in a 45 degree cone that gives satellite footprint between 500 and 700 km, suggesting coverage of the US and Canada needs more than 10 ground stations but less than 100, very dependent on how often outages while satellites do not have both user and base station in sight are acceptable. With 22 satelites per plane and a 96 minute orbit period a new satelite will be along within a couple of minutes and for many uses occasional 5-10 seconds gaps would be acceptable. Not so useful for gaming of course.

The viability of this hybrid business model depends a lot on how effectively Starlink can find pockets of customers and negotiate the necessary terrestrial connectivity in various political entities and against other commercial interests.