My main point though is that it isn't the electronics or the fan's max speed that are the critical parts, it's whether the fan is able to dissipate the heat being generated with the total sum of how everything is set up. If it can't, then temperature creeps up until that max speed is hit (thus it can't dissipate anymore and throttles, hits equilibrium at a higher temperature (because bigger temperature differential means more heat transfer even at the same fan speed, so it's possible it won't just run away when the max speed is hit), or melts/overheats to failure) or until the fan speeds up and is able to find an equilibrium or reduce the temperature.

Thus whatever tricks they use need to result in fans that are still good enough to replace whatever fan they are replacing or they will cause performance issues.

Though if someone is just adding case fans, then as long as it doesn't disrupt the airflow, it will help even if it isn't very good, and you can use multiple quiet fans to replace a single loud one and see an overall improvement even if the individual fans aren't nearly as good as the single one they replace. So based on that, I'll back down from my previous "their reputation speaks for itself" because the reality is that they can be overpriced underperforming garbage but still get a good reputation because they aren't just being evaluated via a/b testing and I was naive to oversimplify it like that.