MMR is not definition of skill for most part, it's just number based on player average performance in matches and amount of hours invested to achieve certain rating goal. There players who have 51% win rate on hero just spam hero 5000-7000 games then achieve 5k mmr while have bad macro decision and even bad item builds on hero all the time There many example such that you can see if you other people replays and actually statistics on website Dotabuff. MMR - is most about how good grinding points rather actually skill level of players because you cannot measure anyone individual skill level with 100% certainty, what you can do measure rank points, win rate, total amount hours, match statistics, KDA, Net Worth, Damage Deal, Last Hits.