They can also improve that balance by adjusting the qualifying times from year to year, and they do.

They could even make a projection of future cutoff times and take that into account when setting the baseline qualifying times. In other words, be a little more generous with the 18-34 group initially knowing that you'll like penalize them more with your one-size-fits-all cutoff. I'm not sure if they do that.

Also, the current qualifying times are all multiples of 5 minutes. If they really want to improve balance between groups, the low-hanging fruit is to make those more granular.