"Otherwise, spammers would rule the first SERPS"
Nope, and that's what frustrates the hell out of the spammers... all the major parts of their formulas (Pagerank, Hilltop, etc.) *are* published, what isn't published (because they change daily) are some of the constants used in the calculations, but all the algo pieces are out there. It's standard reading in IR (which is what SEO would be if it wasn't a bunch of scammers). It's just that for a given page there are two over hundred measurements per page, and spammers are in search of something "quick and easy", rather than take the effort to make pages, and sites, that would wind up at the top of the SERPS.