One of Stanford’s original AI gurus says productivity liftoff has begun after doubling in 2025 amid transition to ‘harvest phase’ along J-curve

The K-shaped economy has dominated discourse lately, but the J-curve is entering the chat too amid debate over AI’s impact on productivity.

The curve refers to the idea that general-purpose technologies like AI don’t produce immediate benefits. Instead, massive investment comes first, obscuring early gains. It’s only after this initial dip that productivity really takes off, resulting in the J shape. But for some, it’s not clear yet that the transformation is happening.

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