It would be nice to have that option. But such a small percentage of the web as a whole chooses to pay for such journalism that it is likely hard to justify implementing that feature. You can search WSJ.com by using the site:wsj.com argument after your keywords, but that isn't really what you're asking for here.
Generally speaking, paid journalism is not a sustainable business model for most entities. WSJ might be an exception, but they won't be getting any special Google treatment, nor should they.
Personally, I believe that the business model of most journalism sites will switch to a combination of sponsored content and the sale of Facebook and Google custom audiences. With retargeting, it's possible for an adveriser, say Microsoft, to tell a site like WSJ "we want to be able to advertise on Facebook/Google to people who read to the bottom of this article you wrote about cloud services" and pay WSJ for being able to use that custom audience. This kind of retargeting is already possible on Facebook and Google, but currently only limited to people that have visited your own site(s). Having a custom audience marketplace would be amazing for many advertisers and deliver badly needed revenue to publications.
Generally speaking, paid journalism is not a sustainable business model for most entities. WSJ might be an exception, but they won't be getting any special Google treatment, nor should they.
Personally, I believe that the business model of most journalism sites will switch to a combination of sponsored content and the sale of Facebook and Google custom audiences. With retargeting, it's possible for an adveriser, say Microsoft, to tell a site like WSJ "we want to be able to advertise on Facebook/Google to people who read to the bottom of this article you wrote about cloud services" and pay WSJ for being able to use that custom audience. This kind of retargeting is already possible on Facebook and Google, but currently only limited to people that have visited your own site(s). Having a custom audience marketplace would be amazing for many advertisers and deliver badly needed revenue to publications.