I think that Medium's response would quite understandably be:

Medium received $0.00 from all those thousands of external views, so has $0.00 to distribute to the author.

However, Medium clearly does benefit from external views by satisfied readers who might become paying members at that point or in the future. It's free advertising for them.

So there should perhaps be a reward system whereby every block of 1,000 non-member views is given a monetary value, for example.

It would be down to Medium to put a figure on the worth to the company of those clicks achieved via a writer's story. The conversion rate is probably very low, so I wouldn't expect much. But if they offered $1/1,000 non-member views that would double your earnings from this story.