The 30 - 40 years part is key. You need to support them for a generation. You need to let the remnants of the old power structure get old and die. The country has to be full of people that were raised with the benefits of the new government.
You can look at Japan for a great example of this type of success.
No big business utilities? PG&E is worth $35 billion. Duke Energy is close to $70 billion. The list goes on. These are fortune 500 companies that employ small towns worth of people.
Utilities are damn near as big as it gets.