Not in my experience. I have #1 spots for some highly competitive keywords and keyphrases, and my pages rank high in Google for many, many other search strings.
In any case, there's no such thing as a site getting pushed to #100 by spammers (or by anything else). Google doesn't index sites; it indexes pages. That's why a content-based strategy is so effective: Every page is a different point of entry for search-engine users, and the "organic" nature of real content means you'll get referrals for search phrases (or variations on search phrases) that you never even thought of. I get nearly 4,000 referrals from Google on a busy weekday, simply because my site has pages on so many different subtopics of my main topic.
Having a content-rich site has advantages that go beyond search-engine referrals:
1) Because the site looks professional and inspires confidence, users can feel comfortable in buying through the site's affiliate partners. (This is important, IMHO, because many users don't distinguish between the site and its partners or advertisers.)
2) It attracts users who are looking for information. If your site is an authoritative, trustworthy source of information on the the topic that interests those users, they'll come back when they're ready to buy.