Ireland is actually pretty compact compared to Africa or Siberia or South America or central Asia, and those are almost certainly not as wealthy as Ireland per-capita.
Are you arguing that there's no economic value to bringing internet to underserved regions like vast territories? Or that those people would be unwilling to pay for it? (They seem to be quite willing to buy mobile phones.)
I don’t think they’re likely to pay enough to justify a high valuation. And remember you’re basically talking just very rural areas in the long term; towns and villages can be hooked up increasingly cheaply. Like, Starlink is maybe a viable medium-sized telco. Maybe even a large one; they might hit Vodafone scale (though probably with a worst cost structure; a lot of Vodafone’s business is just reselling other peoples’ fibre). Note that Vodafone isn’t valued at multiple trillions.
Ultimately, it’s hard to be high margin as a telco.