I found the paper very instructive. Could you explain what's so different today compared to 2004? The paper specifically says ISP can do 100% paid transit, o

I found the paper very instructive. Could you explain what's so different today compared to 2004? The paper specifically says ISP can do 100% paid transit, or 100% peering , or anything in between. If the actual ratio transit/peering is different today, how does it invalidate the paper? The paper raised some good points that can be useful when discussing net neutrality, and also "Facebook Basics" kind of offers.