Matching works by grouping select clusters of mmr within a certain range of each other, and having an approximate average of all players on both sides being similar. ie a side might match 1000,1050,1100,1150, & 1200 mmr against a team of 5 1100’s.
However, those are approximate values as the ‘exact’ number isn’t known (esp for QM,) and there can be a difference between a number trending upward compared to one trending downward. Lotta conspiracy rants see that as “forcing” loses, but since the system uses MMR averaging, there isn’t a difference between a 1200 and a 1200.
While all sorts of people rally to tin-foil theories that suit claims the game “forces” them to lose, the general issue is that said players are clueless, unobservant, and don’t know how to have a bigger impact on what is actually happening, and since they don’t know, it’s easier for them to assume the universe is out to get them personally, so they rally around theories that claim something is out to get them.
Functionally, the matching doesn’t know who does what, and the metrics of a “good player” aren’t so binary, so the system just tries to make guesses based on average performances. Heroes Profile, a third-party site that tracks game stats from uploaded replays (called parsing) indicate you are playing on a low-level account.
From what you may have noticed, outside of grouped players, you’ve likely also encountered other accounts that are lower leveled AND are also played with heroes that have lower levels.
With low level accounts, the game doesn’t know where to seed a player (what mmr they “really” play) and QM gives an extra handicap for the first few levels a player plays on a hero since they’ll usually play worse with lower leveled heroes than they do higher ones.
So functionally, between lower account and low level heroes, there’s a higher range of uncertainty on what the game can anticipate on the MMR value for players, so it’s prone to seemingly dramatic shifts because the game can’t magically know if players are legit new, smurfs, boosted, etc etc esp on lower leveled accounts.
What tends to commonly be the case is a sort of ‘rubberbanding’ on matching certainty. In the 1000 -1200 mmr example, a player with a few games will be on the lower match end of the mmr average and have “better” players in their bloc. As they win games, they are in the same bloc, but now they’re at the higher end, so the average mmr has ‘worse’ players for the same average. ie, when a player was 1000, they may have played with a 1200 in their team, and now that they player is a 1200, they then have a 1000 in their match because they’re still in the same mmr “cluster” with where the matches average the matched mmr.
If the player wins, the confidence the game has in the rating shifts, and they progress upward (in ranked, that’s usually seen with promotions form say bronze to silver, but that’s more decorum than not) If the player loses a couple, then the confidence of the MMR settles and sees the lower value as being closer to the ‘true’ average of the player.
Because there’s a lot of uncertainty at certain ranges of play, it’s not uncommon to see some games flip/flop because there’s no real investment in making a new account and getting a hundred or so levels fairly quickly.
As such, it is harder to discern when players are legit new to the game, rely on friends to take charge, are just goofing around, etc etc.
A number of game metrics try to suggest it takes more than 100 games to actual seed a player, but some of those estimates don’t include as diverse a hero/role system for HotS. And while it should hold that when players have good basics, it shouldn’t matter too much what hero they play, functionally, more of the playerbase is pretty bad at the game, and so long as they have something else to blame for their conduct and losses, they don’t have much incentive to actually improve themselves by knowing, seeing, and doing better.
As some point things do get “better” but it’s not a linear distinction, especially for Quick Match, because players can level up heroes in AI or ARAM modes and essentially undercut any sort of indication that they’d ever actually be ‘better’ at the game regardless of their account level.
Some players have 3000+ levels, and don’t know the distinct objective for each map. So a key part of some of the matching does fall into “luck” especially for players that predominately pick assassin roles. Since there’s too many QM players in non “essential” roles, game experience can be all over the place in having mass assassin/bruiser games where people demand tanks/healers, but never actually play them themselves, and the matching can’t magically produce what doesn’t exist.
So tl;dr, based on what I saw, some of your earlier matches had some benefit of the doubt for newbie queue, and your later series of games may be out of that and you’re in the rut of “well, they’re not “new”” in your matching.