Is it worth getting into? It can be very rewarding on a personal level, as a hobby or obsession. As others mentioned however, if you're eyeballing it as a "career" that you expect to be profitable, look elsewhere.
It can become profitable to varying degrees, once you have experience, equipment, and of course, *talent*. It's not a "trade" you take up like welding or nursing because it's a smart career choice. It's more akin to being an artist. Yes, some few do very well at it, most starve.
Everybody I know that is *only* a full-time knifemaker is either a) retired, b) independantly welthy, c) supported by their spouse, or d) seriously struggling to keep the bills paid.
I don't know a single person that only makes custom knives for a living that doesn't fall into those categories. If they paid for all their equipment, house, and debts from a previous job, they're retired in my book.
You can certainly suplement an income with knifemaking if you're talented, and there are some few that make a good living at it, but its the exception to the rule.