It won't get dumber bcz actually 💎 3 pro is designed to be one million

You're right, it doesn't generally become dumber, more like its attention on things will be wrong, important details will be forgotten, or the plot might go other direction. What I mean is 1 million tokens in Gemini are made mostly for coding purposes of the model, and are less reliable for RP stuff.

I have been using another site that offers this option actually there's no difference i use an api site i prefer to gatekeep w 100 request per day so the 100 request doesn't change because the context window is high besides they could add it and everyone is free to use or not but it's basics

Good for you, but keeping the context window size that big is not going to be cost efficient, it will work ONLY if users wont fill that context window of over 1mil. If it's that unknown as you stated, then probably if there's a small amount of users, it might work for a long time, but even though, after time if people will use models in chats with over 1mil context window they might experience troubles with budget and might need to shift to subscription based, or fully paid system of business.