But at least one technical advocacy group — Trans-Mediterranean Renewable Energy Cooperation (TREC) — suggests that mass production could bring prices down to 5 cents per kWh or less (PDF), even without technical breakthroughs.
The PDF linked is a summary, so I don’t know how good the case is.
I will also note that this price includes enough storage to ensure 70% reliability — which provides different economics than the 95% reliable wind grid component I mentioned previously, and different economics than wind without storage. Obviously sun and wind as grid components mix well together. The troughs — sunless weather and windless weather — tend to occur at different times. So do the peaks — strong winds and blazing sun. (Yes, there are exceptions, Santa Ana winds and so on.)