Too many viruses. There are too many viruses that cause it and they mutate. Be patient. Someday, there will be a cure.
Too expensive. And complicated and it is not serious enough to cause serious complications to warrant the investment.
Not worth it. Cold symptoms result from the death of surface coverings in the nose and throat. The damage is done by the time you know you're sick, and they restore themselves quickly. The rate of healing is almost as fast as the body can do, and even if we had a way to kill the virus without danger or side-effects, it would barely speed the process. Read more...