I don't think it's the question of technology, it's the question of economy, incentives and investment costs.

Even if the clean energy becomes cheaper hydrocarbons can have comparative advantages and when their price goes down it's creating new uses and new demand.

Even if EROI (energy return of investment) of hydrocarbons turns negative, it may be cheaper to use clean energy to extract hydrocarbons from existing sources than transfer CO2 to back to hydrocarbons.

No. Searching "solar in developing countries" suggests it is an ongoing process.