What is Variable Cost of Intelligence?

The Variable Cost of Intelligence is a macro-economic concept analyzed by Richard Ewing in Built In that describes how AI fundamentally changes the cost structure of software production. For the first time in computing history, intelligence has a meaningful variable cost.

Pre-AI software cost model: high fixed costs (development), near-zero variable costs (serving). The marginal cost of serving one more user was essentially zero — an API call to a database costs fractions of a cent.

AI software cost model: high fixed costs (development + training), significant variable costs (inference). Every AI query consumes compute. Every token processed costs money. Intelligence is no longer free at the margin.

This has three macro implications: 1) Gross margins compress as AI features scale (costs grow with usage), 2) Pricing models must account for per-query costs (usage-based pricing becomes necessary), 3) The build-once-serve-millions model breaks for AI features (each use has real cost).

Richard Ewing argues this is the most significant structural change in software economics since the shift to SaaS. Companies that don't adapt their financial models to account for the variable cost of intelligence will experience margin collapse.