Before cloud computing, companies bought servers sized for peak demand and kept spare capacity idle. Cloud providers pooled demand across many businesses. Ten thousand flats each holding emergency inventory is the same shape of problem, and a neighbourhood of algorithmically stocked dark stores is the same shape of answer.
The physical analogy has limits. Inventory cannot be provisioned instantly or duplicated at zero marginal cost. Perishables spoil, forecasting errors have a floor, and delivery capacity gets scarcer when demand spikes. Pooling works best where density is high, which is why this is a story about a small number of large Indian cities—not India as a whole.