Expanding on this, the thing is that Westlaw and Lexis gathered and published content created by the state as part of a sort of reciprocal agreement. West & Lexis used to charge nominal fees for access to print copies of case law, but now the online fees are exorbitant. In order to really research a court opinion you need to skip back though years and years of precedent cases to make full sense of the court's reasoning. Likewise the costs of using treatises on various disciplines of the law have increased several fold in the last decade or so, as hundreds of medium-sized and mom and pop law publishers have been consolidated into two or three giants.
Paywalls are great and necessary to encourage new research and pay for investigative journalism, as you do with New York Times, WSJ and Financial Times subscription support. But it's unfair to have to pay more than modest fees, say $1 to $3 a hit, for content created long ago for virtually nothing.
Regarding the NYPL, what would be great is if a foundation were to set up a project to inventory and describe their valuable Slavic and Asian and other holdings - sort of as the Suda was to Byzantine scholarship.