The generalists that don’t have the particular intersection of skills to be CEO end up being outcompeted by specialists for specialized roles. See: poor wages and working conditions for unskilled workers, who certainly have skills outside of work, but no skills that matter enough in the economy to get specialized jobs
Picking something that is not only interesting to you but also needed by the market is generally a good idea if you want to earn money. Otherwise it’s just a hobby.
But getting tenured? Here, where I live (Western Europe), only the number of papers and european projects you've been into matters, even if the outcome of the "research" of those papers or projects is nothing to be seen (who really controls that?).
If you feel like you’re reaching a glass ceiling, don’t be afraid to go outside that box. Record some lectures and put them online. Self publish a book. Start your own school. Etc. (The exact way you can color outside those lines will heavily depend on your context, but you want to be coloring outside the lines).
Yeah, I have an introductory programming course that I'm developing (like how to think algorithmically with flowcharts and pseudo-code for beginners) adapted from another class I teach, and I'm exploring teaching platforms such as Thinkific and Teachable. I also have some other courses (building a 16-bit OS from scratch, basic data structures, etc.) that I would like to develop as well. This semester I have a lot of class hours, but next semester I plan to put them online (and maybe do a Show HN).
But thanks for your words! It is a confirmation that I really need to do something else (by the side, at least).