Many, many people are told the five year line on being diagnosed. One day it will be true. That doesn't mean that all is lost, you can live well with Parkinson's. And, it doesn't mean there should be less research. The easy approaches haven't led to success, but improved understanding comes all the time (e.g. the role of misfolding alpha-synuclein). One of the problems is that even if we knew the answer it takes many years to go from the test tube to the pharmacy.
And what of us, people with Parkinson's, what can we do? We can be proactive. We can get the most out of what is available now (e.g. try not to eat protein close to taking levodopa); we can follow leads in the research that we can safely adopt (e.g. exercise); we can support the research process (e.g. join clinical trials); AND we can do our own science.
Science is not something that just other people do. Science can be done by anyone. Indeed many people with Parkinson's were scientists and engineers before diagnosis; the skills don't disappear at the moment of diagnosis. Many of the barriers to doing research are breaking down: access to journals over the internet; cheap computer hardware; often free software [e.g. the R statistical programming language]; cheap, accurate measurement tools [e.g. sensors that can track tremor].
What of the person who claims to have no relevant skills. First, this I doubt. At the very least you have 24/7 experience of the disease. And, anyway, one of the features of Parkinson's is that in most people it is slowly progressive. You have, perhaps, 20 years to get up to speed.