There's another thing that separates you from most writers with big followings (you may not consider your following very large but it is compared to most of us). You engage with your readers. Most do not.

Anyway, 3.5 million monthly may seem like a lot, but I worked as an enterprise software developer (I still dabble in semi-retirement) for years and I am willing to bet that it barely covers their costs of doing business. So I'll stand by what I said, your writing will most likely outlast Medium, which eventually will go the way of other platforms that come and go.