To add on, I feel that Blue matured between the events of R/B/Y and G/S/C and does not really have an interest in becoming champion again. His goal throughout R/B/Y was to be higher than Red, as rivals are, and once he achieved that goal, he immediately had his downfall in losing. He tried taking a different route this time, as a gym leader, so he can learn how other trainers use love and strength in battle rather than brute force or as tools. Anyways, that's how I view it.