>>52952194The game sets the goal of 50km/week based on the rewards. So it's assuming you'll get about 2.5 candies a week.
That's 130~ candies a year. So Niantic is saying if you set your legendary as your buddy, you should be able to max them after about 2 and a half years. Really they just want you to whale for raid passes, because walking isn't realistic.
