In your example, both Border's and Amazon have a page about the exact same subject. Amazon said more about the subject, so they won out in quality. This doesn't mean you have to spew all the information imaginable onto a page.
If you have 5 keywords, then 5 great pages of content are going to be much, much better than one huge page of content in achieving rankings for all 5.
Imagine I review fitness equipment. I want to rank for treadmills, ellipticals and exercise bikes. Is it better for me to clutter one page with as many reviews of every treadmill, elliptical and bike as I can? Of course not, I want my treadmills on one page, ellipticals on another, and exercise bikes on another.
But what I want to do is be as substantive and in depth as possible on each of those pages, not some superficial sentence or two. So while I believe you are right, large pages are good, you should not have large pages covering multiple topics and keywords. Go in depth on your one topic and rank for your keyword and its variations.
Back to my example, my treadmill page could rank for treadmills, treadmill reviews, treadmill ratings, best treadmills, home treadmills, etc. If my page covers treadmills, ellipticals and bikes it's definitely not rankings for all those treadmill terms. Targeted content wins, but like you and others are saying, it needs to contain substantial content.