Saying that solar is okay because it's hooked up to the grid is not an answer, because that's just another instance of a reliable energy source (fossil fuels, nuclear, hydro) bailing out an unreliable one (solar, wind).
Sure, coal and gas pickup the remaining tab, but even if they are covering half of the usage, that's better than all of it.
by the same token, price reductions in solar power cost leads to battery storage systems (or other storage systems) being even more desirable and cost-competitive, in turn leading to them being installed in preference over other types of power plants.
1) You're still using MUCH less overall fossil fuels. A 40% reduction in fossil fuel use would do wonders for the world economy and be a huge step forward in reducing emissions. 2) If other people are feeding power back into the grid, then you can be using their solar power. It's sunny somewhere, right?
You can add a battery backup system to cover night-time usage on your own home. The $10k battery system basically doubles the price. But since the solar panel's price just dropped by 50%... Cloudy days you might still be in a deficit.
What is so wrong with a mixed system that uses renewables where it makes sense and relies on other sources to fill in whatever gaps appear?