“Quality of Life” was a category on the survey, although it was only one of ten. Additionally, they were mostly asking the people who were benefitting the most from their society:

a survey of over 17,000 people from 36 countries – including business leaders, middle-class or higher college-educated individuals and “nationally representative” citizens of each country

So I imagine there were a lot of folks who disagreed with the final rankings, but their opinions were mostly considered irrelevant.