First, a lot of people I know would never thank a machine regardless of how happy they are with the results. Second, a lot of people habitually say "thank you" regardless of their actual satisfaction level.
Because of these two things, I doubt that whether or not someone says "thank you" is a strong indicator of satisfaction or dissatisfaction.
Maybe the actual count but it was in the news back in April
Saying ‘Please’ and ‘Thank You’ to ChatGPT Costs OpenAI ‘Tens of Millions of Dollars’
https://www.entrepreneur.com/business-news/saying-thank-you-...