But I think that's the problem: people don't look at subscriptions for news the same way as they look at a gym, for example.

People understand you gotta pay to go to the gym. News, on the other hand, you can get for free (give or take ads and tracking).

The gym question is "am I gonna use this?" The news question is "do I need this?" or "is this sufficiently better than the alternatives to justify the cost?"

Edit: and to touch on the "per-article" aspect, odds are that people might spend let's say ~$2/month with a publisher through article reads, but not $5/month for a subscription.