I'm not sure exactly what your doing .. But I was taking the images from my site - and posting them onto a Pinterest account - and using PinPioneer from BST - to do a bunch of things including adding people, likes, repins etc .. and I was making Sales everyday while I was running the campaign.
So I selected a product of about $200 targeted at a certain niche .. and it didn't convert at normal Google traffic rates - but at least I was getting some sales .. in your case seems your doing something different and that's your issue.
With Amazon it always comes down to this ---- 10,000 site visitors are useless if they aren't buying in 24 hours -- but 50 highly targeted motivated people are -- if you convert 10% of those
and the product is $200 or more - and your sales commission is at least 6% - then your $60+ a day - right there.
I can't tell you how easy Pinterest is today - because I don't use those methods much anymore - Google provides the majority of my traffic -- but like everything you gotta test a few ways before you can find something you can work with.
This reminds me of Twitter and how alot of people say I can't make money there either --- What I used to do there - was say promote Nba Finals Game - Heat / Spurs
go to spurs and heat twitter account - grab all the followers and tweet them a message - special game promotion - Enter your email to win whatever prize it was -- and watch the money roll in
now they are alot stricter with those email submits and twitter -- but you get the idea -- you just got to funnel the right kind of traffic down the pipeline to generate money.
Cheers