Because of the way the internet is, to use a fringe competitor you usually pay more to get less. (Satellite internet, home LTE providers).
Around here, Verizon and ATT recognize that their only competitor is Comcast (or other company on the list to be bought by comcast) so they set their prices slightly higher and rely on marketing to add perceived value for about the same service. It may not be explicit price fixing (though it probably is), but it's still not good for national economic health or security.