Funny that you compare recommendation algorithms to a human being who knows you well. My purely anecdotal feeling is that today, recommending media (let alone a book, as fewer people today read) to a friend or relative is viewed as less appropriate than in the past. When people are facing a glut of content, and are well empowered to find on their own content that would appeal to them, someone saying “You really ought to check this out, I think you’d like it!” might be just as bothersome as friends or relatives trying to evangelize their religion or draft you into their MLM scheme.