AFAIK, they are the least open of the major AI labs. Meta is open-weights and partly open-source. Google DeepMind is mostly closed-weights, but has released a few open models like Gemma. Anthropic's models are fully closed, but they've released their system prompts, safety evals, and have published a fair bit of research (https://www.anthropic.com/research). Anthropic also haven't "released" anything (Sora, GPT-4o realtime) without making it available to customers. All of these groups also have free-usage tiers.

sure but also none of that publicly existed when openai was named

> literally anyone can use it for free, you don't even need an account

how can you access it without an account?

chatgpt.com allowed me to last i checked