Economic unobtainium
Unobtainium is the mythical metal that has unlimited strength and no mass. It's the solution to all difficult engineering problems. It doesn't exist.
There are a lot of people who believe you can have something for nothing. Real economics has it's own version of the Law of Conservation of Matter: it's simplified form is "There ain't no such thing as a free lunch." Like engineering, real economics has to work in the real world. That's why it is sometimes referred to as the "dismal science."
Want to end poverty? Why not set the minimum wage at $50 an hour?
Think government spending is the way to prosperity? Why not raise the federal budget to a quadrillion a year so we can all be rich?