The US government asked the big ISPs how much it would take to wire everyone up to high-speed Internet, then passed a bill to give them a ludicrous lump sum to do so (IIRC it was hundreds of billions). The money was split between dividends, buying up other companies, and suing the federal government for attempting to ask for the thing they’d paid for, and in the end, the government gave up. That left loads of people with no high-speed Internet, and the ISPs able to afford to buy out anyone who attempted to provide a better or cheaper service. Years down the line, once someone with silly amounts of money for a pet project and a fleet of rockets appeared, there was an opportunity for them to provide a product to underserved customers who could subsidise the genuinely impossible-to-run-a-cable-to customers.

If the US had nearly-ubiquitous high-speed terrestrial Internet, there wouldn’t have been enough demand for high-speed satellite Internet to justify making Starlink. I think this is what the other commenter was alluding to.