I am a scientist but not in the medical field, so I can't really give a correct judgement. But to be honest I do believe that strong disease-modifying meds and maybe even the cure is already present in the current pipeline. The problem is that it takes an incredible amount of years before these things are approved and sold.
First, there is GM1 ganglioside. As far as I have read about current clinical trials this is almost like a real cure (in a 5 year clinical trial of 80 patients it looked that people at end of trial were better than at begin of trial). I am still very angry that for some reason the medical world doesn't provide this to PD patients. I personaly contacted the MJFF to ask for the reasons. Then I started to investigate in literature and I could counteract all of these reasons. So as far as I concluded these reasons are all nonsense. I also contacted the doctor doing the research. He told me he had no time to respond at the moment, but that he would do so in future. I am still waiting ...
Second, there is LMTX. This is not tested on Parkinson's disease people yet but it slows down Alzheimer progression with 90 %. It removes the bad proteins in the Alzheimer brain. In 4 years this will be on the market if the clinical phase III can provide the same amazing results as clinical phase II. But LMTX (actually methylene blue) has also been tested on rodents with "PD" with succes. At the moment there is a clinical phase I of LMTX for PD. So this one is also very promising. I guess in 4-5 years from now clinical phase II results should be available; so at the same moment as LMTX is sold for Alzheimer. If these results are good, I am pretty sure that PD patients will get LMTX off label.
Third, there is cogane. Results for clinical phase II are very close to be collected. I think in beginning of 2013 they will reveal whether cogane is disease-modifying or not. I do have great hopes for cogane as this basically causes the brain to release the neurotropic factor BDNF. This is the same one that your brain release when you do sports. Given the fact of the many recent claims that sports is probably disease-modifying for the PD brain, I think this is very hopefull. The good thing is that with cogane the brain can possibly release more BDNF than when you do sports by just swallowing a simple pill. The problem is that if the results are good, a clinical phase III trial is still needed and we have to wait another 4-6 years for these results.
There is also a bunch of other things that are in the pipeline and can "cure" or "slow down" PD. There is BrainStorm Cell Therapeutics. They performed stemcell treatments in clinical phase I. The results were very good. One of the patients was a Jewish rabby and because he didn't have much time to live, they gave him a extra dosis of the treatment. The result was amazing. The guy could walk, speak and swallow normal again (http://www.algemeiner.com/2012/07/05/orthodox-rabbi-may-be-first-als-patient-cured-by-israeli-drug/
). They inserted stemm cells in his brain that release neurotrophic factors. This can also be used on PD patients and I am convinced people with PD will benefit hugely with this approach too.
There are also other compouns in preclinical phase to stop or remove the clumped alpha-synuclein. The Affiris vaccine is even in clinical phase I already and in less than 2 years we will know the first results.
There is a lot coming and I think there are several things in the pipeline that will make a big difference to PD patients and slow down or cure PD. But I think the first real life changing treatment is 4 to 6 years away.