She might be happy as a clam doing what she's doing and has no interest in other stuff. I think we are unique in what we will enjoy doing. I know for me it was back a long time ago. While in grad school I carried the US Mail and although I was fully motivated to get the final degree and the expertise that implies the carrying of the mail never left my thinking. Even today some 46 years later I wish I had never left the Post Office. Nothing ever gave me the same feeling ... well maybe teaching at the University might have but not as adjunct. Folks often say that as a mail man I would make a fraction of what I earned in my field but ya know... money never entered or altered my thinking. Still doesn't! I guess the question is; why does the Artist choose to paint and live like a peasant when she could pursue a field in which she was educated in. I'd hope for everyone the notion that happy is as happy does.
As a sibling with three brothers, I was somehow chosen by my parents, uncles and aunts to be "the pick of the litter" whereby i would go far in life and be some kind of role model or other. That being said, I chose toolmaking as a career choice even though I knew I'd do OK if I stuck it out in college and went for a post grad degree. To complement that occupation, I work out of my home and enjoy doing part-time jobs repairing 'puters and doing event and small wedding photography, although it doesn't help things that I'm right in the middle of doing a complete restoration on a Corvette that I've owned since 1978. <===That right there is an example of stupid is as stupid does.
I've been quite happy being happy in the career of my choice and have absolutely no regrets. I've made contributions to my field of expertise that I'm modestly proud of but most of all, I've been able to help others by passing on to them the experience I gained from being in a job I like for the past 30 some odd years both in the military and in the private sector. That gives me a lot of satisfaction.
Classmates of mine who became doctors, lawyers, engineers etc. (of whom I do not mean to disparage at all)......well, some of them got married to their jobs and didn't seem all that happy to me whenever we got together for mini-reunions and such. Stress was what most of them complained about. That and that ever looming challenge of outdoing themselves and often failing in that regard.
I feel rather fortunate that I found my niche sooner than later. And like you, I realize that all the riches in the world does not compare with finding that certain balance point where life can be something that's simultaneously enjoyable and productive.
So yes, I completely agree with you that "happy is as happy does".