I see what you're saying. Once we need clean fuel for cars, a demand for clean fuel in other markets will be driven up and more readily satisfied.The underlying theory is that producing electricity in a clean way is not so hard and indeed in many places there has been a lot of progress towards wind, solar, hydro etc.
So if all cars were electric and most electricity generation was clean, then it would solve a lot of problems. Eventually.
But from what I hear, persuading all the nations to focus on cleaner energy production is a sticking point. However, if developed nations lead on, perhaps others will follow in time.