You'd have to ask someone more knowledgeable than me to reflect on how the "golden exiles" affected the new Cuba. I'd say that Castro's overreach and the America-led boycott probably had more impact than their leaving.

Where the exiles definitely had an influence was on the politics of Florida. The Cubans, white and wealthy, were given a welcome home in the U.S., and not-so-very-long after our country's own anti-communist spasms, they were a reliable source of pro-capitalist and anti-Castro sentiment.