I like to think of the global human population metaphorically as a human being, and each member of the population as a cell. Some people make up the hands, that move and make things. Other people make up the blood, that carries supplies where they are needed. Anyways, using this metaphor, the sciences and liberal arts both provide brain functions, one providing the practical side, the other providing the impractical side. I think both are necessary, and it's healthy for this human that represents the world to have both of them.
My gripe on the subject though is that liberal artists are in general overly strict and limited. Sciences have to be regulated and they all have to work together in order to progress, that is how they work. Liberal arts, on the other hand, can and should be much more free, and it annoys me when I see very little change in some areas of liberal arts over great lengths of time.
Finally, science is the practical of the two, so that is why it may be thought of as 'more necessary', or easier to get a job with, because jobs are, well, practical. Liberal arts doesn't fit as well with the concept of a 'job', so it may be a bit harder to find something. Even so, I think that liberal arts operates on a much more fluid timescale, with inspiration or insight occurring at such irregular intervals that a 40 hour workweek is most likely not the best way to produce. Perhaps in the future, there will be an expansion of more free flowing careers in the liberal arts with less strict requirements that will enable us to better support liberal arts as a global community.