It's tough to predict the future, especially since technologies change all the time.
But if you master the fundamentals of a particular area that interests you, you might be in a better position to respond to whatever is hot/upcoming at the time.
In Web there's always a hot new thing in frameworks/tools but the underlying tech/fundamentals have remained the same e.g. HTML, CSS, the DOM, etc.
It's tough to predict the future, especially since technologies change all the time.
But if you master the fundamentals of a particular area that interests you, you might be in a better position to respond to whatever is hot/upcoming at the time.
In Web there's always a hot new thing in frameworks/tools but the underlying tech/fundamentals have remained the same e.g. HTML, CSS, the DOM, etc.