Regarding coal, it's mostly getting crushed by natural gas, not solar or wind. The last ten years of data shows coal has declined about 600,000 GWh, roughly a third of its 2006 output. In the same time, non-hydro renewables have increased about 225,000 GWh (of which solar makes up about 100,000 GWh). Natural gas increased about 500,000 GWh. Total generation increased about 140,000 GWh. Past performance is no indicator of the future, of course, but when people talk about the decline of the coal industry over the past decade, they're also talking about the rise of gas.
I agree. While the regulations cost money, undoing them won't budge the market much.
Not sure how good this data is but I may be wrong on cost per MW/h. But the data in the table bellow shows gas as being 30% cheaper so not sure. https://en.wikipedia.org/wiki/Cost_of_electricity_by_source#Energy_Information_Administration. From my college energy textbook I remember 30% cheaper being in the ballpark but i guess numbers vary based on how you calculate the total cost..png)