Can governments pick winners?

The short answer is, most likely, no. Two minutes on this question from Dave Donaldson.

Examples of geographical clustering in industries, such as Silicon Valley, suggest that firms have potentially positive external effects on other firms' productivities. Dave Donaldson discusses his research on the extent to which this is taking place, the strength of these economies of scale - for firms, workers, and consumers - and the role the government can play to foster this.