JSTOR does exactly this with scholarly journals, and it works out pretty well. Recent issues are accessible only to paying customers.

Back issues (usually at least a few years old) are available via JSTOR for free in small amounts and through subscriptions for bulk users. I'm sure there's some reason to fight about the details, but from a distance it looks like a pretty good compromise.

Newspapers think their archives are worth money, and that people who are interested in genealogy will pay for newspapers.com subscriptions.

Agreed. IA should take snapshots of the articles over time and then make them publicly available X months/years later. There's no reason to immediately publicly mirror the articles beyond people trying to get around paywalls.