The foundation models on which they're built are only GPT-3 capable, and what most many people run locally are the lightest weight, quantized weights, so their performance is even more degraded.

LLaMA-based models are popular because LLaMA beat GPT-3 on benchmarks. But ChatGPT runs on 3.5 Turbo and later, beating them.

There's currently no open model that compares.