I feel your pain, but I don't think it's that bad. I'm not a friend of Medium and I have more than 10 reads on some stories - not all, admittedly. Could it be that the story is news and has already been seen by interested parties? I don't know. It does seem odd when you think something should go viral and only 5 people are interested.
It seems to me there's a lot of focus on two things here: engaging a lot helps, and being boosted helps. Otherwise, it's down to followers and luck. You may find many of your 6000 followers are bots. I had 1000 bots follow me last month.
Anyway, Medium circulated this story in my weekly newsletter today, so they don't hate you.
Hope that helps.
Not sure Substack is a great improvement. They don't pay at all, unless you have individual subscribers.