Guys its not a permanent decision they made, we can see huge improvement of sales in categories which they dropped the commission rate these days,
If they are going keep this commission rate in further as well, they will loosing good links and seo power which comes from affliate sites, amazon keep their top ranking for every category with support from network of affliate sites , dont think they want to see less brand visibility in serps, im pretty sure they are more analytical than saving few dollars by rereducing the rate