Well if you make the argument that it will replace terrestrial networks and that's why its worth X trillion $ then yes, you do actually need to cover the 1% of earth surface where the waste majority of people actually spend most of their time.
The question is not if its a good business, the question if its a 2 trillion $ business, and if you only cover the 95% of earth without coverage. That more like a couple 100 billion $ business at best.
In regions like Nigeria or the Philippines, Starlink costs over 100% of the average monthly income. The individual addressable rural market really is closer to 1% than 40%.
Starlink Mobile actually reinforces my point. Most don't have phones capable of using it. And even at that, it’s a low-bandwidth designed for SMS and emergency data, not a primary ISP replacement. Of course, you can believe what it could be... Much like all of Elons products, they are always coming
The question is not if its a good business, the question if its a 2 trillion $ business, and if you only cover the 95% of earth without coverage. That more like a couple 100 billion $ business at best.