Generators also are an expensive proposition. However, as the industry moves more towards centralised power, the economics for natural gas improve. A single gas line essentially provides the power needs for an entire network. That's a lot of little boxes in front yards. You should expect some neighbourhood resistance.
Someone needs to conduct a successful evaluation of fuel cells, and then a field trial.
Another major hurdle is cost. Although natural gas cells are in the works, most observers say the only acceptable fuels are any of several types of light hydrocarbon mixtures. Not only do these provide more energy than an equivalent amount of natural gas, they are cleaner-burning and thus less damaging to the environment. And the cost problem is likely to be temporary. It's not just the cable industry that's looking at it.