2. if all works out, I'm booked for the next 24 month straight - if I do not have clients' projects I have more than enough own projects to work on (I actually wish for some time off for years, but it never happened)
3. I do not live in the us, but in a rich economy and I am comfortable financially; compared to many people I know I live a simple life, why is probably why I do not need to charge $100+ or more - I'm in the top 10% wealth bracket already and looking forward to three more productive decades.
I know people with way less experience charging more, but I'm in no rush.
I was lucky that my open source contributions led to some interesting short and long term engagements. If I'm already into something, it may be that I find it interesting - no need to search.
I believe, if you can maintain a genuine interest in certain, contemporary topics than you will probably have an easier time to stay relevant.
Today, depending on your interest, I'd probably would go deep into the "devops" field, since that's quite technical, fast moving but with lots of stable parts (like operating systems) and there's demand and will be for some more time.
There's also always a way to stay relevant by just being very good at a very particular thing - even if there are only a few jobs. I remember mainframe people advertising that if you know your way around z/OS you'll never have to search for a job again.
In my ears, knowledge graph sounds a bit grandiloquent. I do not have a definition, but I know that when talking about knowledge as it is embodied in people, it's quite a subtle thing, hard to formalize and to be honest, something relatively rare.
Why can we just call these things fact databases?
Add. Knowledge evokes a lot of other associations as well, for example that what we are able to know changes over time. That a time has a certain underlying grid, into which certain factual stories appear and later disappear.