Only to a certain extent. It's largely outweighed by the amount of benefit your credit score is receiving by eventually having multiple aged accounts. What the OP is describing is essentially a way for people to trade points from their credit score (provided people are at a level of disposable income to start playing this game) for straight up cash or loyalty points.
> Doesn't opening that many accounts every year hurt your credit score?
Yes.
However, you'll still be in the 80th+ percentile of credit scores. Additionally, the number of applications you've made contribute only around 10% to your credit score.