Why do parents usually stop their children from pursuing a school or a career in writing?

Parents are usually looking out for their children and when they themselves haven't come across instances in their life where their interest was of use to them in some way or the other, it tends to create a set mentality that pursuing your interests is secondary to having actual career goals and get into the usual market that the world is running on. However the world is so much more vast out there that the possibilities are endless and children who are interested in writing should definitely be allowed to pursue it as a career. Rather than stopping their children from it, parents should consider directing their interest in such a way that there is growth in all aspects, with their base being their interest,

Its mostly due to peer pressure from their parents when they were in school; a traditionalist mentality that some careers are more profitable than others therefore, need to be pursued regardless of interest from the child. Lack of knowledge about the outside world is also prominent in some parents, especially stay-at-home mothers who are not aware of other things that are profitable and maybe more interesting to their child. 

Many parents, especially in the Middle East, do not see writing as a lucrative career. They need to be well-informed about the literary field.