We can ask why those areas with no competition are so, and it is due to overwhelming anti-market bias that makes it hard for other ISPs to compete or even outlaws it directly. Meanwhile cities that have setup one touch laws or fixed right-of-way have seen robust competition emerge.
One area where markets do poorly are where the cost of service exceeds profit, like rural areas. This is an area where government intervention in the form of subsidies can help, but these can also cement single ISP marketplaces if not managed well.
Sounds to me like ISPs should be regulated or managed the same way as telephone and electricity providers
Along with healthcare
People don't seem to have issues getting electricity service or telephone service in those regions. In this case, the special treatment of those services means that people don't get left out
Rich people aren't the only ones who deserve healthcare or good internet
One area where markets do poorly are where the cost of service exceeds profit, like rural areas. This is an area where government intervention in the form of subsidies can help, but these can also cement single ISP marketplaces if not managed well.