In writing code, from what I've seen, Anthropic's models are still the most widely used. I would venture that over 50% of vibe coded apps, garbage though they are, are written by Claude Code. And they capture the most market in real coding shops as well, from what I've seen.

What data are you basing your assumption on? OpenRouter? That itself is only used by a tiny fraction of people. According to the latest available numbers, OpenAI has ~800x more monthly active users than OpenRouter. So even if only 0.5% of them use it for code, it will dwarf everything that Anthropic's models produce.