It's not an absolute rule but it is the preference of the majority of people. There are many who will only be successful through their own efforts however it's only an extremely long-lasting thing when you've got enough time to test it.
However, the majority of players are not patient and desire to experience the excitement of playing. They believe the process of farming OSRS Gold is an automated process and therefore they are more inclined to pay a tiny amount of money to acquire OSRS from a reliable site Gold and this is the most popular choice for players.
Based on my experiences, I prefer to purchase it through the RSorder site, due to the fact that it is quick to deliver and the security is high, and there's practically zero risk. It is also possible to try it.