The most important market signal this week was not that oil fell, AI stocks wobbled, or bond yields moved. It was that markets have begun asking a different question.

For the past two years investors have focused almost exclusively on scarcity. Scarcity of GPUs. Scarcity of power. Scarcity of data-centre capacity. Scarcity of memory. Scarcity of AI talent. Scarcity of investment opportunities capable of delivering meaningful earnings growth.

That scarcity mindset created extraordinary winners. Nvidia became one of the most valuable companies in his...