Click rates on organic search results are much higher, and there is a tendency for users to have more trust in the legitimacy of Google’s organic results than in that of paid results with AdWords. In 2014, around 77% of clicks resulting from search results went to organic results, with only the remainder pointing to other options: click on paid results or no click at all.
First place in organic results in Google generally got more clicks than all paid results combined: 31.24%!
Looking at the data for 2018, in spite of recent efforts by Google to make paid results look almost identical to organic ones, the situation is much the same, with the distribution of clicks between organic and paid being almost identical. These results are explained by the natural psychological tendency to avoid straight-forward persuasion. We all have it! You will notice it is much harder to convince a friend of something if you start by saying: I will now begin my efforts to convince you.
Yet, there is not a universal consensus in terms of such data. Some are providing data to show that organic results have been losing clicks, especially on mobile searches and product-oriented searches. Yet, the total number of clicks for neither category has decreased, since the total number of searches on Google keeps growing.
Imagine you are getting a slightly smaller part of a much larger pie. Even 15% of a huge pie would be enough to keep pay per click services happy.