There's no money in it, so they don't research. And from a doctor's perspective, a natural cure could work, but the problem is with dosing. With pharmaceuticals, they know exactly how much to prescribe and that you'll receive the necessary amount.
Another problem is that people can be unreliable about following a course of treatments. They stop as soon as they feel better. This is evidenced by the misuse of antibiotics, which require increasingly more powerful versions because people don't take a full course, causing bacteria to adapt and become more resistant.
We should explore all options, I agree. But it doesn't necessarily mean we'll use remedies effectively.
RE: Is nature powerful enough to cure diseases?