Technology does profoundly alter people's views of the world
Even in the scientific field, people create theories based on what they see around them. In the Middle Ages, people tried to understand the world as a type of clockwork mechanism. Now, people try to see what goes on inside their minds as types of computer programs.
Granted, it's not the same as saying "cell phones make all people rude and inconsiderate." But, the more interactive a cell phone becomes, such as the jump from cell phones to smartphones, the more demanding they become. This means they will draw more on people's finite attention span, which means they will have less left over to interact with the world. Over time, this will indeed cause people to value other people and the outside world far less, and the world that goes on inside their phone far more.
If we compare this to a computer or computer game, most people don't bring their PC with them everywhere, and even portable game systems must be turned on and interacted with. So these can be put down and attention paid to the world around the person.
In contrast, cell phones, by their nature, demand attention any time one receives a phone call or other data-driven notification such as text message received. That's not to say they're not highly useful, but many people let their cell phones rule them because they demand attention. So, the net effect is more interactive cell phones -> less interactive people, since both are pulling on the same finite resource.