The Reality Check: Your Python Script is a Money Pit We’ve all been there: you find a cool model like CatVTON for virtual try-on or Wan 2.1 for video generation on GitHub. You wrap it in a FastAPI, deploy it to a GPU instance, and—boom. Your cloud bill hits $500 before you even get your first 10 paying users. In 2026, the "AI Tax" is real. If you are running raw PyTorch code in production, you aren't just running a model; you're subsidizing NVIDIA’s next headquarters. The "Python Overhead" is Killing Your Scale Python is great for prototyping, but it's a bottleneck for high-frequency AI. Specialists with decades of experience in high-performance computing don't just "run" models. They compile them. Numba to the Rescue: For heavy pre-processing (like image masks for furniture placement), use @njit. Converting your Python logic into LLVM-compiled machine code can shave 200ms off every request.…