I prefer the current matchmaking system over Voobly, but that doesn’t mean the current matchmaking system is great.
In games like CS:GO, League of Legends and Dota it’s already known that the matchmaking is trying to give you as close to 50% win-lose ratio, because that’s what keeps most players engaged, if you win all the time eventually you get bored, if you lose all the time eventually you get mad an quit. CS:GO and League of Legends are already known to have a public ELO and a real ELO, the public ELO is there so you think games are balanced, the real ELO is your actual skill.
If you win 3 games in a row, eventually you’ll have much harder games because the game wants you to lose. So you get to a point where you really have to carry if you want to advance through the rank.
It isn’t far fetched that something similar is happening in Age of Empires 2 as well, because unlike real sports like chess (that ELO is based on) the goal of a video game is to keep you engaged, not to be the most accurate system for determining a player’s skill.
Not to mention, matchmaking in chess, football and tennis are open-source, everybody can see how the matchmaking works inside-out, so that the system can be checked for fairness. This is literally not the case in video games where the matchmaking system is closed-source, nobody knows it but the developers.
Maybe there’s some confirmation bias on my part, but the fact remains what when I intentionally started being the worst player on my team and stopped being the carry if I saw that my teammates were terrible, I ended up getting far more favorable matches afterwards.
Not only that, but I used to play mostly with a real life friend, I would carry him, always having far bigger score. When he & I would play team but not together, I would almost always have games where I had to be the carry, while he would almost always have games where he was carried (just like he was being carried by me).
Maybe the game is using your ending match score to determine your true ELO, it isn’t far-fetched.