To be honest, I didn't find DuckDuckGo's AI on the top of their search to be very good anyway compared to the one Google has. However can't say I have cared much as typically if I am searching I don't want an AI response, otherwise I'd just go straight to an AI chat interface in the first place.
Biggest problem is that google has a near exclusive deal with reddit, so all other search engines have old reddit results [1].
The Google one is personalized to use language and sources that you'd prefer. They're building an individual response for each person that is most suited to trick that person into clicking on their ads. For some people they dont care, but I myself dont want a digital clone of me tricking me into buying things.
Salesman have for a long time teaching new salesman to use NLP tricks like matching and mirroring to convince people you're relatable and trustworthy. Google is doing this with all the data they have on you.