For gas, coal, or fossil fuels you have to pay to extract, refine, and transport the fuels - then also have to build and run the infrastructure to burn it for energy.

Solar and wind you generate and "extract" in one go. The solar panels/plant is collecting and generating power at once. The wind turbine is collecting and generating power at once. There's no shipping or pipelining sunlight and wind.

The "cost" of mining/extraction is basically non-existent. You've gotta buy fuel to burn it. You don't have to buy sunlight or wind to generate power of fit.

That on top of it being cheaper and easier to roll out solar panels and wind farms than it is these other power plants, and the lower cost is clear.