Here's the announcement from one of the principal engineers:
Journalism is labor
I hate and block ads, since they literally screw up the functioning of the page now, so I don't think they should "just have ads and be open" -- but I think expecting average non-journalists to sign up for subscriptions to multiple "national newspapers" and a half dozen news magazines is absurd, which is why people here don't like paywalls, and bypass them wherever possible.