Google has gotten better in the SEO game with some new rules and updates every now and then, and it is better in most cases, just not all.
Search the web and you will find websites that rank 1 on Google owing to the backlinks that they’ve accumulated instead of actual useful content.
While it is undeniable that the factors that rank websites have only gotten better, it is also true that there still are loopholes that allow one factor (backlinks in the above case) to make all the difference. This is one of the greatest shortcomings that exist in SEO and SERP in general.