Readers of scientific papers never had to pay. Before papers were available in digital form, you could request a paper copy from the authors. Of course the auth

Readers of scientific papers never had to pay. Before papers were available in digital form, you could request a paper copy from the authors. Of course the authors usually paid for some extra copies for this but when those ran out, you'd get a photocopy. Then people started requesting a copy and would get one by email. Now it's just faster to simply find that copy on the web than wait for someone to reply to your email.