Since 5.5 came out they kept on nerfing gpt-5.x-pro models in the browser.
It used to reason for 30+ minutes and give well-rounded in-depth answers.
Then, since a couple of days ago it just reasoned 10 minutes tops and started giving useless answers.
Today I woke up to this veeeery nice new crappy UI (why do they keep on changing the core ChatGPT UI anyway?) and GPT-5.x-Pro is just unusable.
I'm using Extended Pro thinking and, I swear, it DID NOT think at all!
Stupid answer it gave. Ok. I will try again with 5.4 pro instead of 5.5 pro.
Now it thought for 3 minutes and a half lol. Still a useless generic answer.
Then I tried to just use regular 5.5 Thinking on Heavy, and it thought for around 10 minutes and gave a pretty good answer.
I used to upgrade from the 20$ plan to the 200$ one just because I would have access to GPT Pro models...
Now that moat is also gone.