The matchmaking algorithm is the unsung hero that determines exactly who you will face every time you press the 'Battle' button.

While this conspiracy theory is widespread, the reality is much more mundane and focused entirely on mathematical fairness.
The Elo System Adapted
Your trophy count is a numerical representation of your skill; win a match, and you take trophies from the loser.

This is why winning streaks inevitably end in a 'wall' of difficult matches; the system is functioning exactly as intended.
The algorithm does not care what deck you are playing.If you face a hard counter, it is pure statistical variance.It helps them learn before facing real humans. The Free-to-Play Dilemma
The standard Elo system works perfectly for chess because all pieces are equal, but tower rush games feature upgradeable cards.

However, if no such player is available, the algorithm will prioritize queue speed over level fairness, resulting in those frustrating, mismatched games.
Conspiracy TheoryThe TruthForced Loss StreaksThe algorithm does not force losses; you are simply playing tilted against harder opponents because your MMR is inflatedThe Deck Counter CodeDevelopers have confirmed repeatedly that the algorithm does not read the contents of your deck when finding an opponent True Fairness
This is why all true esports tournaments and competitive challenges utilize the 'Tournament Standard' ruleset.

The algorithm is blind; it only respects victory.