Playing chess for 5 hours a day does not make chess your "sole study and business" unless you have some disorder forcing you to sleep for 19 hours a day. If you spent the rest of your waking time studying chess, playing practice games, and doing the minimal amount necessary to survive (eating, etc.), THEN chess is your "sole study and business"; otherwise, you spend less than 1/3 your waking life on it, which is less than people spend at a regular full time job (at least in the US).