Solar cost per megawatt hour is MUCH cheaper than anything else beside wind, so really it's the lack of grid storage that slow mass adoption. If you have grid storage at $20 per mega watt hour then most places can't afford not to switch to solar because running their coal and gas plants is 30%+ more expensive than gas and probably around 100% more expensive than coal. They might not switch over immediately, but the downward price trend will continue for solar/wind and energy storage and you'll probably only get higher fossil fuel prices as volume of sales decline while the tech also isn't improving.