For some people, your concern is justified. There is a point where your Carbodopa/Levodopa will stop working or not work as well. That 10 years is not set in stone however. Some people I know have been on it over 20 years. I have been on carbo/levo for 13 years and it still works as good today as it did when I started.

As for new drugs, welcome to the merry-go-round called slow progress. There have been many drugs that show promise that end up on the shelf or completely dropped from the investgative process due to lack of money, lack of caring, or something. Then there are those that just fail to workout.

Take a deep breath, relax as much as you can, and hold on for a bumpy ride.