We have seen John Mueller of Google respond to this question before, the question of why does my competitor rank above me when they are doing X, Y and Z wrong. Why does this site rank when they are spamming or have lower quality content, etc. The answer is typically short and to the point; that is, the site is doing other things well and well enough to rank high in Google.
In this past Friday’s SEO hangout with John Mueller, he addressed the question again but in much longer form. Longer than he ever has, from what I’ve seen. He spoke about this for about seven minutes. I am not going to transcribe it, but I will use Glenn Gabe’s tweets as a summary and embed the video where he starts talking about this so you can listen yourself.
In short, why does a site that implements bad SEO practices rank well in Google?
A site does not need to do everything perfectly to rank well
Google has many algorithms to evaluate a site
Hence the image I used, it is like a balancing act
Google often ignores the bad things, so they don’t help the site rank but also do not always hurt the site from ranking
Larger site pictures are important over the long term
Focus on overall value to your users
Ask your users if they like your site, use surveys and focus studies