When you subscribe to a publication, you have to make decision once. You think about the amount of money against all future potential articles you can read, and decide from there. When you're paying for EACH article, all of a sudden you have to make that decision with every click. Is this article REALLY worth 50 cents?
Not to mention, this incentivizes the totally wrong things. People say they hate clickbait, but the aggregators and social networks that now act as gatekeepers force that kind of behavior -- publishers of course only get paid when you click through to their article. And in this case, it's even more profound -- we're no longer talking about a few cents from display ads, but 50 cents to $1.
For what its worth, we're trying a different tack -- especially when it comes to local news: https://blog.nillium.com/what-can-napster-teach-local-news/