I find it odd that the initial announcement mentioned Aaron Swartz, but not Greg Maxwell. Aaron never actually released anything while Greg actually released basically the same things that they are 'graciously' giving out for free now... only after someone forced their hand and yet at the same time denying it is the cause.
These articles are from 1923 and before in the USA and from 1870 and before in other countries, so historic scientific research from the 1930's and later is still behind the paywall.
"Hey, uh all that content we no longer have any rights to, uh, now you can get it for free can you imagine?"
An announcement would be if they made journal articles before 1960 free.