Important to note that electrical grids and markets are more complicated than "average levelized cost". The uptake of intermittent resources will increase the need for ancillary services, and skew the economics towards generators that are flexible.
For example, you can end up in a situation where half the time the price is zero (even negative) and the other half the price is set by your peaking plants. If you own a wind farm, you're likely to be produce most of your energy in low value periods. This effect worsens as you get more renewables. Hydropower owners dominate in this environment, as they can save their water when the prices are low, and sell at peak capacity when it is high. Norway is making a killing on this, for example.
There are also limits to the proportion of renewables you can have generating at any moment in a synchronous area. At present it is likely around 50-60% for most grids (see DS3 project at Eirgrid, where they're closer to 70%). This is largely due to grid inertia and ancillary services. The remaining 30% is interesting. At present the best option is natural gas, to act as peaking, with some old conventional plants hanging in just to eek out value before decommissioning. In the future this may be hydrogen plants and nuclear. In the far future it may be fusion.