Viruses like the common cold and influenza, and HIV for that matter are almost impossible to have this wonderful 'one shot cure'. The reason why is referred to I believe as antigenic drift. An antigen is considered anything that causes an immune response in your body, i.e. GENerating ANTIbodies. In this case, it would be the outer coat of the virus, since this is what your body comes into direct contact with. The problem with the viruses that cause colds, the flu and HIV amongst many others is that these antigens keep changing.
When the virus infects you and uses your body as a factory to make more copies of itself, it carries with it some of the machinery that it uses to make these copies. In these viruses, this machinery is essentially defective because it makes mistakes. Not huge mistakes, but big enough to alter what the virus "looks like" to your body.
What a vaccine (one shot cure) does is presents to your body, in some form or another these antigens without the invasive infectious stuff with it, so the body can go ahead and prepare itself (via complicated measures you don't want me to get into) for the next encounter with it.
This is the reason you only get things like the chickenpox once. The chickenpox virus doesnt change constantly like colds the flu and HIV does, so once your body has devloped specific defensive measures against it, it can't fully reinfect you. A minor infection could occur, but your immune system would put it down before anything drastic happened, since its seen it before.
Now, colds, the flu and HIV are constantly changing, so there is no way to 'show' your body what the coating of the virus looks like so it can ready its defenes, simply because the outer coat is constantly changing. This is why HIV kills you, it's coat changes so fast that your immune system literally can't keep up with it, so it can't generate proper defenses against it, since a big part of your immune response is based off of these devloped defenses to the coat of the virus. As well as why you need to get a flu shot every year. The flu virus changes, albeit not as much as HIV but it still does. We then look at what particular 'coats' are going to be most popular in the US each year, and make a vaccine accordingly. Colds and HIV change to fast for even somthing like this to be effective, sadly.
Now, I can understand your point as to companies make lots of money by not looking for a cure for colds and the flu, and this is probably why not much research was done on finding a cure, but HIV is a whole other story. Since the worldwide epidemic of HIV has occured, tons more research has gone into studying viruses that change coats so fast, and some vaccines are being tried out, but so far every one that has been tried has failed
so people continue to die.
Sorry for the long post, just wanted to clear some things up that I thought were inaccurate...