This solved topic from five months ago is about the OpenAI API for software developers. At that time, GPT-4 was available in ChatGPT Plus, but in very limited availability to developers.
Your concern now is specifically about subscribing to ChatGPT Plus. It unlocks not just access to GPT-4 to chat with, but other features. Registration was closed two weeks ago in unprecedented action due to limited resources. Except for that information contained next to the wait list button, no other information about the future is available.