Find XO: Open weights arrive at frontier quality for one-sixth the cost, business margin calculations built on APIs go awry (martinalderson.com)

- Z.ai's open-weight model GLM 5.2 outperformed GPT-5.5 on coding benchmarks, with output costs of $4.40 per million tokens compared to Opus 4.8's $25. - Businesses that layered wrappers on closed APIs to earn margins are seeing their cost floors collapse completely. - Competitors see the same cost sheets, so the savings flow to customers rather than founders. - The lowered costs are more a notification that prices cannot be maintained than an opportunity.