Yes i do believe that competition among cell phone carriers will mean lower overall prices with the release of the new iPhone 6. When a new and updated phone or any other piece of technology comes out the old models prices will definitely drop. People don't want to buy old models when they are as much as the new ones.
This is exactly how it should work in the market. More and more companies are competing on the prices of their phones and nowadays you can almost always get a great phone for free with the purchase of an extended contract. I think this will be a great things in the long run for customers.
Yes, I do think the competition among cell phone carriers will eventually lead to a decrease in plan rates. The bottom line, competition is the ultimate factor in bringing out the best in a company. If a well-known carrier is offering lower interest rates, that respected carrier will do their best to offer the same. It's about keeping the customers happy, especially when there are alternatives out there.
Think of how much more you spend today on cell phones for your entire family than you ever spent on home phone service. This is an example of technology making things more expensive, not less. People will continue to pay large amounts for the iPhone 6 because it is an inelastic good that people want no matter what.