The incentive was to make Chile the Silicon Valley of Latam. The SUP vision is to "Convert Chile into the innovation and entrepreneurship hub of Latin America by attracting the world’s best and brightest entrepreneurs to bootstrap their startups in Chile."
Notice it doesn't say anything about people staying, just about people coming. Of course that if no one stays there is no ecosystem, but this is a work in progress. By attracting nerds, they got at least one part right (http://www.paulgraham.com/siliconvalley.html).
The chicken/egg problem is that we can't find follow-on investment here, so we leave. But if we leave, no VC will want to be here to make follow-on investments. What should we do?