I think it's more a matter of being lucky enough to enjoy doing something which is valuable to others. It's easy to love what you do if your hobby is in demand.
Sometimes even those are pretty shitty jobs, though. My hobby is art.
Commissions really suck sometimes, as they aren't creative and generally aren't enough to live on. Comic book artists often work long days only to be greeted with pain at the end of the day. Hand cramps are the least of the worries: such artists often develop problems with their dominant arm, commonly carpal tunnel and tennis elbow. And these are usually contract jobs with no benefits whatsoever.
My mother is an excellent seamstress. Most paid work is wedding alterations, tailoring clothing, and sewing patches on military uniforms (decent demand here for quality work, which she does). That work absolutely bores her and she winds up hating her hobby.
Of course, these aren't exactly in demand per se but is illustrative of how things change once you are working for it. It really isn't all that easy.
Even if your hobby is in demand, that still doesn't mean you'll love doing it on somebody else's terms. Like, I enjoy developing software, but I've had projects that I didn't particularly enjoy and constraints that rendered seemingly-enjoyable projects miserable.
I think it's more a matter of being lucky enough to enjoy doing something which is valuable to others.
Another way of looking at this is: rather than basing your enjoyment of life on pursuing a pleasant hobby (which you may or may not be able to get paid for), instead derive your
enjoyment from doing things that need to be done.
In our society that translates roughly to "earning a living by helping others". If this is your source of satisfaction, you don't need very much luck.
