Anthropic as a company only was created after GPT-3 (Dario Amodei's name is even on the GPT-3 paper).

So, in same time OpenAI have gone from GPT-3 to GPT-4, Anthropic have gone from startup to Claude-1 to Claude-2 to Claude-3 which beats GPT-4 !

It's not just Anthropic having three releases in time it took OpenAI to have one, but also that they did so from a standing start in terms of developers, infrastructure, training data, etc. OpenAI had everything in place as they continued from GPT-3 to GPT-4.