Because the phone service provider would need to build out infrastructure to provide internet over the usual copper wiring to those homes; typically called DSL. Some phone providers just don’t do that. There are other technologies to use, including the now operational Starlink that use low orbit satellites launched by SpaceX and Elon Musk. This is high speed and coverage will worldwide. It covers much of the US now for beta testers numbering 60,000+.
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