A look at case studies suggests that yes, indeed, official business incubators do help fledgling enterprises. They generally provide reasonably priced space, but, more importantly, enable entrepreneurs to make vital contacts relatively easily. In all fairness, it should be added that the same contacts, and more, are available to any ambitious entrepreneur, wherever they choose to locate.
Incubators add value to new companies by providing a window on their existence.
One of the success stories of the 1980s was Lotus Development. I happened to see the office in which they had spent some of their early days in Cambridge, Massachusetts. Most commonly, the major stimulants are a nearby university and financing sources. There are many facilities that are basically unofficial business incubators. If the company needs a manufacturing, distribution, or other special space, there are numerous business and industrial parks available for the young company.