Comments on your last paragraph: Your example is, indeed "funny" but needs to be fleshed out more. On the surface the argument would be true, but IF AND ONLY IF (as is the environmentalist's implicit belief) the cost of those alternatives did not also (probably) increase. That's a perfect example of the sputtering of brain cells that passes for "thinking" these days: It never occurs to these liberal arts majors that if (fossil) energy costs rise, that is because there were huge increases in its inputs (petroleum, natural gas, etc.) due to changed supply and demand. One doesn't need a degree in economics to know that these raw materials underlie essentially all modern civilization. As such, increases in them will feed into nearly all products and services, including the true costs of making, transporting and maintaining all their precious windmills, solar plants, hydrogen farms and so on.

A deeper analysis would consider other possibilities too, such as that if no other alternative existed, people might scrimp on other purchases so that they could continue paying for accustomed fossil fuel usage, or (more likely) they would simply use less and at the extreme, none at all, if the resource became too costly or simply unattainable.

Economics is, in fact, a useful field of study (As with many so-called "sciences," it rather falls short of being worthy of that name; that is but one more example of "borrowing" a venerated brand name and applying it to a shoddy product, like our mRNA "vaccines"). Its descriptive and predictive value drop quickly once you get beyond the very elementary bits like supply and demand.