From my observation, some people wait until they become graduates before looking forward to acquiring a skill, although there is nothing bad about it. But, come on, why not acquire a skill before hitting the university? And when you are there, you will definitely get little or high exposure if your skill is something simple and a service that people frequently desire. In my university days, there were these guys in the hostel: one was a barber, one was an artist that made designs on cloth, and one was a photographer, and they would all go out to do their work and still have time to study. Based on the advice you got, a small-scale business cannot yet make much profit, but if it's possible to start the business and put someone in charge of managing it while you still learn your skill, do so.
and be realistic about it, some needs to pay their debts so they gotta work. some of them are also breadwinners, so whatever they earn, will go to the basic needs of their family. but if the person has the inclination in enriching himself despite of the situation, he will find time to hone his skills as it will be his advantage over the others. there will be sacrifices but later on, he will reap the rewards of his hard work.