I agree with most of the observations, although I think that 1. and 8. contradict each other a bit.
In my opinion leaving your comfort zone often, so becoming kind of a 'generalist' is a good strategy only if you can learn subjects quite deeply quite quickly, which needs some kind of raw intelligence. Among the successful scientists/engineers only the the extremely intelligent could be successful in relatively different topics in my opinion.
I'd say it's more 'preference for learning' than just raw intelligence. Like with the whole 10,000 hours thing; if person A spends 5 hours a day studying while person B spends those same 5 hours (watching TV|gaming|socialising with friends and family), then in a couple of years person A will know a hellova lot more stuff than person B, regardless of intelligence.
If you want to be a Python specialist, for example, working at a job where you do exclusively Python and you get paid more and more as you gain expertise, then your time is probably better spent learning Python and not branching out.
If you're more of a "full-stack" developer, you might continue to learn new languages and paradigms, understanding the underlying concepts but maybe never learning language-specific fringe cases. Someone who does this might enjoy learning, and might prefer to switch things up and change jobs every few years.
If you want to start your own company, you'll probably want to be even more of a generalist, not focusing on development entirely. You might have a bit of a specialty in one area (software development or sales), but you'll want to know enough about all areas of running a business to be able to understand what's going on -- but you might want to hire the experts to know and learn more about any one of the areas than you do.
"only the the extremely intelligent could be successful in relatively different topics"
I'd disagree based on experience, not that I'm a successful generalist idiot (although I might be) but its extremely well known in the field, that learning your 8th language or 4th paradigm or 1000th fad or whatever is about 10x easier than learning your 2nd.
Learning one language is hard, but it scales back rapidly. How many different glyphs and syntax and formatting style can possibly exist to describe recursion, or addition, anyway?
In my opinion leaving your comfort zone often, so becoming kind of a 'generalist' is a good strategy only if you can learn subjects quite deeply quite quickly, which needs some kind of raw intelligence. Among the successful scientists/engineers only the the extremely intelligent could be successful in relatively different topics in my opinion.