AI is like a colander. Customers pour in. Many pour out.

How many customers does a model retain after one month, two months, or three months? The answer lands somewhere between a social network & a mobile game.

What do you have with half an AI? Cohort retention across AI models, SaaS, social media, & mobile games

Software companies retain roughly 90% of customers through the first five months, an aggressive assumption. Facebook & Instagram hold closer to 80%. A typical mobile game keeps a few percent. Models land somewhere between high single digits & about 40%, with the stickiest foundational cohorts near the top of that range at month five.1

The average frontier model maintains its crown for 41 days.2 The king is dead, long live the king, is a nearly monthly chant.

This pattern isn’t changing. Two days ago, OpenAI published this chart showing a surge of users for its newest model, Sol. The token growth chart is even steeper.

OpenAI usage chart for Sol, July 2026

Benchmarks are no longer purely performance-based. They include cost. Microsoft’s MAI-Code-1-Flash matches Claude Haiku 4.5 on SWE-Bench Verified using 60% fewer tokens.3

For the financial readers, this is the equivalent of the PEG ratio4, where value is normalized by another metric. Here, intelligence is normalized by dollar.

Artificial Analysis : Cost per Intelligence Index Task, 12 Jul 2026

Artificial Analysis measures the same phenomenon at the frontier. GPT 5.5 & Claude Opus 4.8 score within a point of each other on the Intelligence Index near 60. GPT 5.5 is 28% less expensive to run.5

xAI’s Grok 4.5 lands one tier below, at a score of 54, & runs the Intelligence Index at $0.31 per task, 60% less.6

The price for a given level of benchmark performance is falling roughly 10x per year on frontier knowledge, reasoning, math, & software engineering tasks.7

Unlike the instability of the Middle Ages, this war of the weights benefits the community. Startups build on whichever model wins this month & re-route next month. Customers gain negotiating leverage every 41 days.

  1. OpenRouter & a16z, State of AI : An Empirical 100 Trillion Token Study with OpenRouter — https://arxiv.org/abs/2601.10088 ↩︎

  2. Tomasz Tunguz, Darwin’s Finches in AI — https://tomtunguz.com/time-to-replicate/ ↩︎

  3. Tomasz Tunguz, Intelligence Per Dollar — https://tomtunguz.com/tokens-per-result/ ↩︎

  4. PEG ratio (price/earnings-to-growth) : a valuation metric that divides a stock’s price-to-earnings multiple by its earnings growth rate, normalizing valuation by growth. ↩︎

  5. Artificial Analysis, Intelligence Index — https://artificialanalysis.ai/evaluations/artificial-analysis-intelligence-index ↩︎

  6. Artificial Analysis, Grok 4.5 brings xAI to the intelligence frontier — https://artificialanalysis.ai/articles/grok-4-5-brings-spacexai-to-the-the-intelligence-frontier ↩︎

  7. Artificial Analysis & Epoch AI, The Price of Progress : Price Performance & the Future of AI — https://arxiv.org/html/2511.23455v2 ↩︎