why haven’t we found a cure for the "common cold"?

why haven\’t we found a cure for the "common cold"?

there are so many diseases without cure for example: Alzheimers, cancer, diebetes, HIV/AIDS, asthma, arthritis, allergies, chronic fatigue syndrome, eczema, hemorrhoids, hepatitis, herpes, hypertension, influenza, insomnia, leprosy, leukemia, meningitis, migraine, paralysis, parkinson’s disease, psoriasis, rheumatism, and the list goes on and on…are we wasting our tax payers money on these doctors and scientists? why are these diseases still here? the stem cell research was a promising solution in curing most of these diseases..why did they abolished it?