Claude 3 Opus is in the capability ballpark of GPT-4, GPT-3.5 has alternatives that are cheaper (Claude 3 Haiku) or cheaper and work offline (Qwen 1.5, Mixtral, …).
Is Claude 3 Opus generating more profits and taking considerable amount of customers from OpenAI? I'm not seeing that yet. Granted, I'm in Europe (outside of EU) so I can't pay for Opus but I guess that kinda confirms my statement. GPT4 is still a good product and there are no market pressures to release GPT5.