My dc are presumably in the same age bracket as your niece, and, the two that are working are pretty fulfilled in their jobs, and have both bought houses for FAR less than £375K though nowhere near as low as £60K .
I agree with one of the first replies, pointing out that you can 'be fulfilled' in a job, and not find it boring, without "loving it" and "having a passion for it" 24/7.
I'm retired now, but look back on my working life feeling it was pretty good overall, but that doesn't mean I sprang out of bed every Monday morning, wishing I could spend even more hours working. Just it was 'worthwhile' and the way I did my job made a difference to the lives of many people over the years. Of course there were things about it that were frustrating or annoying, but that doesn't mean, taking it as a whole, it wasn't fulfilling.
My dc feel the same about their jobs.
IMO, you spend more time at work than anywhere else, or doing anything else during your working life, so it is no bad thing to encourage anyone, whatever age, to try to find something they enjoy, or are challenged by (in a good way). That doesn't mean telling them to only work in a job that is "brilliant" 100% of the time, it means looking at the whole package and asking if it is something you are glad you have done.