Gym costs absolutely scale with usage. Equipment wears faster under heavier use. Cleaning and maintenance staff hours scale with how much the facility is used. Consumables like towels, soap, and chalk go faster. HVAC runs harder. The reason gyms can offer flat-rate pricing is that they bet on under-utilization, not that costs are flat.

Setting that aside, even if we accept your argument that gym costs barely scale with usage, then that makes gyms a bad comparison case for Anthropic, whose costs directly scale with usage. You can't use the gym model to defend Anthropic's pricing decisions if the two cost structures are nothing alike.

I'm arguing that both gyms and Anthropic have usage costs that scale with usage, but gym business model assumes a large margin of under-utilization and there's a hard cap to "power user" - I think both of those extremes don't apply to Anthropic's situation. Under-utilizers aren't paying for AI they have a free tier. There's also a natural ceiling on how much any one person can use a gym. There's no equivalent constraint on API usage.