AI 替代浪潮：三大力量重塑成本结构
The Substitution Wave in AI
三大力量重塑 AI 成本：前沿闭源模型持续涨价，开源模型在多数场景已足够好，买家开始替代。Coinbase 将提示词路由至更便宜模型，成本持平但 token 用量指数增长。Lindy 全切至 DeepSeek v4，节省数百万美元且多项核心性能提升。Harvey 在 Legal Agent Benchmark 上通过 SFT 使 Kimi 2.6 all-pass 率达 15%，超越 Opus 的 14%，同一 100 任务成本 $84 vs $954（约 11 倍价差）。Cursor 后训练 Kimi K2.5 得到 Composer 2.5，称其“性能优异且效率高达同类模型 10 倍”。闭源越来越贵，开源平价且性能接近，选择决定企业单位经济学的斜率。
Tunguz 用 Coinbase、Lindy 等真实案例，把「用开源/便宜模型替代昂贵前沿模型」的趋势讲透了，做 AI 应用的人该重新算一下单位经济账。
In short : AI buyers across enterprise, app, and seller layers are substituting cheaper open-source models for frontier closed models. The savings don't shrink the AI bill — they get reinvested in exponentially more tokens per task.
Three forces are reshaping the AI cost structure :
- Foundation labs are moving up the stack into applications,1 2
- Frontier model prices keep rising for the smartest models,3
- Open-source models have crossed the good enough threshold for most use cases.4 5
The natural response from AI buyers is substitution.
Coinbase6 :
At Coinbase we’re working hot on routing prompts to cheaper models where appropriate, & in some cases have been able to keep costs roughly flat, while token usage continues to grow exponentially.
Lindy7 :
Pulled the trigger today & switched 100% of Lindy traffic to DeepSeek v4, churning from Anthropic models. Saves us millions of $ & we’re actually seeing an increase in performance on many core use cases. Transformative for the business.
Harvey8 :
On a 100-task slice of our Legal Agent Benchmark (LAB), SFT moved Kimi 2.6’s all-pass rate from 11% to 15%, beating Opus’ 14%. But the cost gap was even more striking : $84 vs $954 across the same 100 tasks, or ~11x cheaper.
Cursor went further. They post-trained Kimi K2.5 into their own production model, Composer.9
Composer 2.5 is exceptionally intelligent & up to 10x more efficient than similarly capable models.
Coinbase’s quote shows where the savings go : costs flat, tokens exponential. Buyers don’t pocket the discount — they spend it on more intelligence.
Closed models are getting more expensive at the frontier; open models are getting cheaper at parity. The choice is which slope you want under your unit economics.
来源：Tomer Tunguz 博客（VC 分析） · tomtunguz.com