Now that paid search ads are taking up more organic real estate, click-through rates for organic search listings — especially in the first two positions — will probably decrease because the organic results have been pushed farther down the page. Indeed, on mobile, we were already seeing SERPs where no organic listings appeared above the fold.
Now that paid ads take away more space in the natural ranking, the point-in rate of natural ranking results, especially the top two, may fall as ads push them further below. In fact, on the mobile side, we've seen search results pages that don't have natural ranking results.
Since the organic search results will be relegated to further down the list, this will cause more advertisers to get more visibility from the top paid search ads, but it comes at a high cost.
As natural ranking results are squeezed, top-ranked ads gain more visibility, but the cost increases.