And power plants don't run 24x7, they're regularly down for maintenance. With either solution you need to over provision.
If I have to provide 100 units of energy (peak) a wind/solar farm that produces 100 units of energy (max) doesn't cut it. Solar obviously varies with time of day and doesn't particularly match actual demand curves. Wind is very unpredictable and can generate 0 units of energy when it is needed and 100 units of energy when it isn't needed. So you still need to have 100 units of capacity coming from traditional systems (coal/gas/nuclear). Congratulations you are now using renewables perhaps 30-40% of the time, still building/maintaining your existing systems, and everybody's electric bill has doubled or tripled.
See southern Australia or Germany for real life examples of the problems caused by relying too much on renewables.
Pumping water up a hill using solar and harvesting the kinetic energy has been proposed numerous times but it's a matter of social will to build the infrastructure to support such projects. Imagine if we built massive offshore tanks to pump sea water into and released them overnight. Inland areas would need a different solution if they didn't want to modify the landscape too much, but I think we can find a balance between traditional batteries and natural "batteries".
Onshore wind is cheaper than coal, gas or nuclear energy when the costs of ‘external’ factors like air quality, human toxicity and climate change are taken into account, according to an EU analysis (in 2014).
The report says that for every megawatt hour (MW/h) of electricity generated, onshore wind costs roughly €105 (£83) per MW/h, compared to gas and coal which can cost up to around €164 and €233 per MW/h, respectively.
Nuclear power, offshore wind and solar energy are all comparably inexpensive generators, at roughly €125 per MW/h."
Well run countries take advantage of this to save themselves money (e.g. subsidies to solar have paid for themselves even if you solely count reduced mortality rates from pollution.)
Oligarchies use a lack of understanding of this to extract out the last bit of wealth from their citizens that they can before the market comes for them.
A recent MIT study examined exactly what contributed to the price declines and government support accounted for the vast majority of the price decline:
http://news.mit.edu/2018/explaining-dropping-solar-cost-1120