Nah....
I also believe the lengthening of cycles by carriers is what lulled Apple into just updating the iPhone design every three or more years.
If anything, carriers shortened cycles by removing the two-year contract. People can upgrade their phone any time they want now, instead of waiting for a new contract promotion to get one for free or at a discount.
The longer cycles are because new designs take a long time to build the machinery and tooling required to manufacture and assemble them, especially with the huge numbers of units Apple needs to ship when a new model is launched. A three year cycle allows them to recoup the tooling investment for a longer time instead of having to retool again for another redesign.