What if Google switches to all paid advertising and search results become irrelevant?
Google, nor any of the other major search engines, will ever switch to entirely paid advertising because the organic search results are the search engines entire product. It is because of the amazing ability to take any search criteria (of which over 50% is completely unique!) and return results in a very accurate order of relevancy that allows them the opportunity to sell advertising and other products. If Google abandoned organic search, they would be out of business very quickly. Search engines’ abandoning of organic search results is about as likely as the sun ceasing to rise.