AI products with a Product-Led Growth motion face a fundamental flaw in their unit economics. Customers expect predictable SaaS-like pricing (e.g., $20/month), but the company's costs are usage-based. This creates an inverse relationship where higher user engagement leads directly to lower or negative margins.

A key challenge for agentic AI products is their business model. Unlike chatbots that incur costs per request, agentic systems that run continuously in the background have non-zero marginal costs, making freemium or low-cost models difficult to sustain.

As more companies integrate AI, their costs are tied to variable usage (e.g., tokens, inference). This is causing a profound, economy-wide transformation away from predictable seat-based subscriptions towards more dynamic usage-based models to align costs with revenue.

Unlike traditional SaaS, achieving product-market fit in AI is not enough for survival. The high and variable costs of model inference mean that as usage grows, companies can scale directly into unprofitability. This makes developing cost-efficient infrastructure a critical moat and survival strategy, not just an optimization.

AI development isn't free; it shifts the economic model of software from zero marginal cost to one with variable costs based on token consumption. This makes Cost of Goods Sold (COGS) a critical, and often new, metric for SaaS founders.

Traditional SaaS models benefited from near-zero costs for new users. AI's high computational and token costs upend this, creating deeply unprofitable users and workflows unless firms carefully manage implementation and pricing.

Unlike traditional software's zero marginal costs, AI-powered apps incur significant inference expenses that scale with users. One founder estimated needing $25M just for 100k monthly actives, challenging the classic VC model for consumer startups.

The dominant per-user-per-month SaaS business model is becoming obsolete for AI-native companies. The new standard is consumption or outcome-based pricing. Customers will pay for the specific task an AI completes or the value it generates, not for a seat license, fundamentally changing how software is sold.

Sam Yagan notes that while the internet made publishing free, AI introduces a marginal cost for every user interaction via token fees. This creates a COGS for consumer tech companies for the first time, forcing founders to reconsider unit economics in a way previous generations didn't have to.