CUDA as Platform Lock‑In

CUDA is not just a programming API but a layered, highly‑tuned software ecosystem that makes GPUs into a platform, preserving Nvidia's market power by forcing ML stacks to target its hardware. Deep, hand‑tuned libraries and even PTX‑level optimizations create switching costs larger than raw silicon performance differences. — If software stacks, not just chips, determine who wins AI, policy and competition debates must shift from fabs and tariffs to platform ecosystems and developer tooling.