Writing is a very minor part of my income. I have done work for SAIC, Capital One, Google, Disney, etc. - I write mostly because I meet interesting people and I enjoy the process a lot.
This is great! Looking fwd to your book on graph database ML. In case you've been using Graph Convolutions, this might be interesting / useful for you: [https://arxiv.org/abs/1905.00067]
arxiv.org/abs/1905.00067