I’m not an engineer, but I can take a crack at this. The forced 50% win rate discussion is weird and complicated because it’s both true and not true at the same time, and people often inject their own biases very heavily on games to support what they think is happening to them, usually to assign blame for a loss to an external source (in this case the matchmaker) because it’s an easy thing to do (the matchmaker can’t defend itself after all!). First, let’s discuss what forced 50% isn’t.
Forced 50% isn’t the matchmaker putting potatoes on your team because you had a win streak. Frankly it’s hard enough just to find good games that there’s no way we would program such a thing, and there is no incentive for us to. We are incentivized to find matches of equally skilled players in our games because they are the most fun overall, which is what the matchmaker always tries to do.
The way it does this is by assigning a skill level to every player as they play our game called MMR. This skill rating is based on whether or not you win or lose games and nothing else (this is up for debate and some day we may find improvements in the future in how MMR is calculated, but there are many good reasons for this and almost every game uses this kind of system to determine player skill. I’d recommend watching some informational videos on how MMR/ELO works if you’re really interested in the nitty gritty). What the matchmaker does is tries to find games where each team has as close to an average MMR as possible while also having the MMR between each player be in as small a range as possible.
Now, imagine that everyone in the entire game has a MMR of 1, meaning that everyone has the same skill level. If we play an infinite amount of games, then everyone will eventually have a win rate of 50%, since their skill is the same. The 50% win rate of those players isn’t the matchmaker punishing those who have win or loss streaks, it’s just a natural consequence of the matchmaker working properly.
In real life it’s not quite so cut and dry since every player doesn’t have exactly the same MMR, but the fundamentals still hold true. As you win games, your MMR gets higher, which means that you will get into games with higher and higher skilled players until you hit your “ceiling”, where you start to lose games because you are the worst person in the game and bring your team down. Conversely, as you lose lots of games your MMR goes down until you eventually get into games where you are the best person on your team. The matchmaker getting you to a 50% win rate is a natural consequence of the matchmaker finding where you, over a long period of time, actually belong. Your MMR being an accurate reflection of your skill results in the natural consequence of you having something very close to a 50% win rate.
Keep in mind also that even 10+ win and loss streak games are perfectly natural in the realm of statistics, even when the true chance of something is 50%. These win and loss streaks are often what people point to as proof that something’s broken, which is simply not true. If you were to flip a coin 10,000 you would not get heads, then tails, then heads, then tails again over and over. Over those 10,000 times you would get each result half the time overall, but you would see streaks of getting heads or tails. This is also true for players who are at their appropriate MMR but still get streaks. It’s not that the matchmaker is broken, it’s just how things are. Also keep in mind that people have good and bad days, and sometimes decide to throw or to try extra hard to win. These behavior changes on an individual game level are impossible to predict and account for, which is why some games, even when they should be evenly matched, can still easily be blowouts.
This is just scratching the surface of how these things work, but again, for a TL:DR:
- The idea that the matchmaker forces you to win or lose after having streaks is completely false
- Having a 50% win rate over time does happen and is “true” in that it’s the result of the matchmaker finding your proper place in the game over time