To the best of my admittedly limited knowledge on the subject, they're relatively new so most news sites aren't terribly aware of them yet, and most people aren't technology-savvy enough to be aware of their existence and ability to make use of them outside circles like ours here on HN and related occupations/sites/etc. That said, they're also not doing anything shady to get by the paywall either. The version they're presenting you is the exact same version the news sites are presenting search engines in order to grab search engine traffic. The news sites are literally participating in an intentional bait-and-switch scheme to bait people with relevant search results that are NOT paywalled, then when a human browser gets there, they throw up a paywalled version in your face via user agent detection, mandatory javascript, etc. (various means are used). archive.ph simply mimics a search engine indexer to get an un-paywalled version, same as Google or any other search engine, in order to retrieve the cleaned up version of the article without a paywall there, and serves that content to the end user. It's not stealing content not already offered in other forms anyway, it's just removing an artificial dark pattern that's literally intended to bait and switch people in the first place. Kind of makes for a weak argument if they do bring it to court in the first place; glass houses, throwing stones and all that.
(If anyone is feeling generous, Archive.today accepts donations at https://liberapay.com/archiveis/donate . The “Donate” link on the site header also links to that URL.)
Testimonial: I've observed mere users on Facebook using archive.ph and web.archive.org to make "backups" of pages they think will be taken down. Not wide usage to be sure but definitely outside of the techie/HN type community.
My guess is that people in the media are pretty aware of how to bypass paywalls because they have to do it to do their jobs (it used to be you could log into most of them with "media/media"; even The New York Times admits that reporters don't get paid enough to afford subscriptions to all of the newspapers that they need to use for fact checking and investigation.)
Most "paywalls" can be bypassed with a clear-cookies or incognito window. They're not actually strong walls, they just want to be annoying enough that some people signup.
