It can be, as long as the people running it know what they are doing. What is their track record? What are their credentials? Can you do better on your own by hiring a business coach or mentor to guide and help educate you in the fundamentals and process of business? These are some things to consider in your own due diligence before going blindly into an "incubator" scenario.
The fall in new company starts does not necessarily mean that the American economy is less dynamic than it used to be, or that Americans are opening up new establishments at a lower rate than they did in the late 1970s.