"Strong" is usually defined in terms of output. And I think we tend to forget that economy is
literally people going around their day-to-day things - we tend to forget about that because our abstract models of it are, well, abstract. But if you, say, tell half of your population to not work, that's half of your economy. Not only that, but it's the half that actually produces physical goods. Take a strong man, and paralyze them waist down - are they still strong? Does it mean they weren't strong before?
The more interesting question is how much of our economy is literally waste. I suspect we'll find out.
