The situation you're describing is the day/night cycle. Currently, solar energy is 4x as expensive to produce (including capital & fuel costs) as coal/gas/nuclear. The efficiency of most solar panels is ~15%. It would take four-fold increase in in efficiency just to get even with our current cost of generation for all other methods. But wait, we didn't account for the fact that the energy needs to be stored for the nighttime use. Even assuming this liquified air system's unrealistic 70% efficiencies, it would require solar cells to have 86% efficiency. That's very fortunate as it happens to be the Shockley–Queisser theoretical limit for solar cells with infinite layers. We've gained about 0.5%/year in solar cell efficiency since 1980. At these rates, we should be hitting the theoretical limit, oh say, in 2130. So, there you have it, in a best case scenario, you need 2100s solar cell technology to match 1800s coal technology and 1950s nuclear technology electricity generation cost. Do you agree with me that solar is useless?
Now as to wind. It should be noted that it's also subject to day/night cycles, but the variance of peak times in different locations make it a little more palatable. However, off-peak energy storage is not really the problem here anyway. Offshore wind generation is similar in cost to solar, but with the exception that wind turbines are already operating close to peak realistic efficiency (unless you have a way of eliminating friction as a force). It means that it will never become competitive with other energy sources.
Onshore wind is slightly better. In fact, according to Parsons Brinckerhoff study it's directly comparable to nuclear (8-11 vs 8-10.5p/kWh). That's with one small caveat. It didn't account for all the subsidies and tax breaks given to wind power. If it had, you would be looking at 1.5-2x the cost of coal/gas/nuclear. Note that economy of scale doesn't apply to wind. The windiest spots that are cheapest to develop get snatched up first. It means that wind power would actually get more expensive, not less, as it's scaled up. And that's before we take into account having to store excess peak power due to wind variability. It doesn't matter whether their efficiency is 25% or 70%. Wind will never become economical. And that's in the UK, which is one of the best countries to utilize wind in. What's everyone else supposed to do?
In conclusion, we both made up our minds. I did so based on current and projected figures and you based on a pipe dream that may happen around the corner. That's all fine and dandy, as long as the ruling class doesn't socialize the cost of that pipe dream. I, for one, don't see why I have to pay higher fees for energy, so that you can have a warm and fuzzy feeling generated by the marketing campaigns of environmental lobby.