Samuel Michael "Sam" Simonwas an American director, producer, writer, animal rights activist, boxing manager, tournament poker player, and philanthropist, most noted as co-creator of the television series The Simpsons... (wikipedia)
Most residential consumers don't spend a lot of time scrutinizing their bills and they don't want to change. The carriers know this.
For a lot of people it makes sense to look at bundling first, because in bringing all of your business to one company you're regarded as a better customer and you could stand to save some money.
If you're an MCI customer, you really don't need to do anything. In the incredible event that something happens to your service, you can always dial around.