I totally agree that we aren't playing actual players live. It may be actual games that players have played, and simulations, but we aren't playing someone live. I've also noticed 2 other trends.
1. Streak manipulations.
As my streak get longs (around the 8 wins mark) the opponent's score starts to reach my personal record for that particular Battle. I think it's all a scheme to get players to spend gems, which I've stopped doing.
2. The league doesn't appear to have real people
Also, I've noticed that the league's leader board appears to match my frequency of play. Last time I advanced from Gold to Jade, the top scores were all in the 600s. This time, when I've played less regularly, the top scores are in the 300s. I think the leader board is just an algorithm and not actual players. The goal being to get push players to spend more time in the app, watch more adds for rewards, and optimize this behavior without burning people out.