In the US, wireline ISPs generally have a government-granted monopoly on the area that they serve. They don't really have a lot of incentive to provide quality customer service.
If you want a speed increase, switch ISPs. If all of the ISPs in your area give provide you with shit speeds, you could look into the agreements these ISPs have with your local government to see if they're breaching that agreement. If you find something, you can bring it to the attention of your city council (or whatever your equivalent is), although chances are that you won't.
If you really, really, REALLY want faster speeds, you could get a leased line, but be prepared to pay $$$$$ for it.