Why do they need to survey every CEO? As long as you have a large enough sample size that represents the larger group, you can get a really good idea of the general consensus. Looking at the KPMG report: "Our latest edition of the KPMG CEO Outlook analyzed insights from more than 1,300 CEOs at large companies globally, including 400 in the United States, to evaluate how they are continuing to navigate the challenge of compound volatility.", which is pretty good if we are considering large companies.

That's not how polling and statistics work.