A SaaS invoice is a beautifully clean number. One line, one currency, no mention of what it took to produce. That cleanliness is the product. Underneath it sits a pyramid where each layer abstracts away the one below, until the physical base is completely invisible on your bill.

The stack, top to bottom

• SaaS cost: the subscription, priced on value delivered, not cost incurred.
• Token cost: what the model actually charges to think, hidden behind the subscription.
• Compute cost: the chips and datacenter time the tokens consume.
• Physical cost: the energy, the minerals in the silicon, and the land the datacenter sits on.

Each layer exists to hide the volatility of the one beneath it. The subscription is smooth and predictable precisely because the token, compute, and physical layers are not. Someone is absorbing that volatility, and in the AI era it is increasingly the vendor, betting that per-unit costs fall faster than usage rises. That is the bet behind every flat-rate AI plan.

Follow the cost all the way down and "software margin" stops looking like magic. It looks like a claim on power, on minerals, and on real estate, packaged so well you forgot it was physical. The margin is real, but it is borrowed from an abstraction that only holds while energy stays cheap and chips stay available.

Software feels weightless because someone else is carrying the weight. The invoice is where they hand you the light end.

Shailin Dhar

The reason this matters now is that the base is where the AI era’s real constraints live. You cannot prompt your way past a power grid or a mineral supply chain. When the abstraction leaks, it leaks from the bottom, and the clean number on the invoice is the last place you will see it coming.