The clustering you see is because they're all optimized for the same benchmarks. In the real world OpenAI is already ahead of the rest, and Grok doesn't even belong in the same group (not that it's not a remarkable achievement to start from scratch and have a working production model in 1-2 years, and integrate it with twitter in a way that works). And Google is Google - kinda hard for them not to be in the top, for now.