Martin Casado says Cursor's founders spend 30-40% of their time on hiring and culture, and that focus is how they iterate so fast: "A lot of these AI companies that I work with are so research-heavy. If you're not working on a new model architecture, it's kind of hard to actually interest the core teams." "They always kept the main thing the main thing, which is changing how you write software. They believed fundamentally it was a product problem... The model's very, very important, but it…