That's like saying for a person who cares less about contests, obtaining Milotic would be "nearly impossible." Getting a certain amount of EVs is not hard at all - it's actually a lot easier than getting a specific total in Contest stats, since you can re-do EV training.
It would likely not be a feasible evolution method, though, due to its difficulty to do during the main story. EVs are an advanced technique anyway; I'm not sure how many kids could wrap their heads around a concept like needing 200 Attack EVs to evolve.