At least four or five US companies have the technical capability to train frontier models, but they face structural predicaments. The industry-recognized efficient method of 'distillation' requires using outputs from stronger models, but OpenAI and Anthropic's terms of service explicitly prohibit using model outputs to train competing models.
Thompson points out that US open-weight model makers comply with frontier labs' terms of service, resulting in weaker models compared to competitors that do not comply. Additionally, talent and capital are siphoned by OpenAI, Anthropic, and Google, making it difficult for remaining startups to produce equivalent work with a tenth of the resources.
On July 15, 2026, Thinking Machines Lab, led by former OpenAI CTO Mira Murati, released Inkling, a 975-billion-parameter open-weight model under the Apache 2.0 license, but acknowledged its positioning as 'a good base for fine-tuning,' not a frontier model. This demonstrates how locked the open-source path has become.