Not OP but I have a thought here: For engineers early in their career, I'd say you probably want to focus on tech that is adopted but not generally viewed as h

Not OP but I have a thought here: For engineers early in their career, I'd say you probably want to focus on tech that is adopted but not generally viewed as heading towards obsolescence (React or Java are in this category, for example). Mid to late career it can be smart to latch onto tech in its growth phase if you believe in it. For example if you were early on the Kubernetes train and managed to build those skills well you're worth a lot of money right now. Actually making that kind of judgment call probably isn't smart when you're junior because you're unlikely to have the kind of experience and instincts to consistently pick winners.