Like in May of the school year before. Then they would schedule mandatory summer practices once a week all summer long to get ready for the contest. (Don't say this didn't happen, I personally know a program that did this, and no, they didn't win)
It's not about teaching our own kids vs something else. It's about not gearing an entire school year (or worse, multiple school years) towards three songs that you record to earn a "spot" showing how great you are as a director. It's about preserving the integrity of the process.
Maybe you haven't paid attention because you admittedly haven't entered in decades. The fact is, it's a huge deal for some programs, and with some directors treating it as a metaphorical genital measuring contest, they needed to reel back some of the more blatant cheating that was going on.