The apprenticeship system has been used in arts and trades for centuries, and many modern art students still put in time with experienced artists in this type of work relationship. Fortunately, they are no longer badly paid servants who are expected to sleep in freezing attics. There are generally schooling requirements they must first obtain, and then they apply for the chance to work with the artist of their choice. If they are lucky, they will be accepted.
It may seem strange that this old-fashioned way of learning is still in use today, but it is there because it offers a variety of benefits for new artists. They study under an accomplished artist to perfect their own techniques while learning additional ways of creating art. It also gives them a chance to study how the artist works to create their masterpieces. When their apprenticeship is done, they generally find many more opportunities than those who do not go through this process.