To give you an idea of just how much money is being spent on paid search, take a look at Google. Google's AdWords program is the most used pay-per-click (PPC) advertising program available today. While the tech giant owns YouTube and Android, among hundreds of other profitable brands, AdWords accounts for roughly 70% of their revenue -- which speaks wonders for its effectiveness.
The thing about SEO in 2018 is that Google changes its algorithms more than once a day! Reports say that the company changes its algorithms up to 600 times a year. While the majority of those updates consist of smaller changes, among them is the occasional, major update like Hummingbird or Panda that can really wreak havoc with your traffic and search rankings.