While not as popular as he was, he's still pretty big. I think the main reason is likely because he hasn't published a new book since 2019, though that's coming in September later this year.

https://trends.google.com/trends/explore?date=all&q=%2Fm%2F0...

https://www.amazon.com/-/en/Dan-Ariely-ebook/dp/B0BQMZXC3T