[quote=Turtlicious]
Isn't it a sunk cost fallacy to keep spending money on a broken thing you plan to replace, because you've already spent money on it?
[/quote]

Planning on inventing a new medicine to delay the end result of a terminal illness is not a good reason to stop taking the medicine that's already keeping you alive, even if it has a bad after taste.

This isn't a "selling your old car" kind of problem. You can't just get a rental for a few days while you're replacing the entire world's transportation, energy and manufacturing infrastructure. Demand is constantly increasing, too, in spite of alternative energy proposals.

 The point is cemented further when we consider that, in this case, we don't know what the replacement for our metaphorical medicine will even be, or even if there's anything that can possibly replace it at all. In all likelihood, we will always be using petroleum to some extent.