Comment by brendank310

I think you're largely correct but Google isn't one person so there may be somewhat emergent patterns that work from an SEO standpoint that don't have a solid answer to Why. If I were an SEO customer I would ask for some proof but that isn't the market they're targeting. There was an old saying in the tennis instruction business that there was a bunch of 'bend your knees, fifty please'. So lots of snakeoil salesman but some salesman sell stuff that works.