That may work for those hitters, but they're not the average. They are well above that level, which is why we're looking at them.
Hitting is about timing. Many girls don't put in the kind of work to get that four or five frame swing you keep talking about. Or they don't have the athleticism. But that doesn't mean they'll never hit. They have to adjust to what they can do.
Getting the toe down earlier puts them in a position to be able to swing on time, whereas maybe they couldn't otherwise.
In a perfect world you can follow what you see on video to the letter. In the real world, maybe not, especially when it comes to timing issues. Just as in a perfect world every player would be able to run to first in 2.7. But they can't.
Average hitters aren't facing Pac 10 pitching either. If you have to get your foot down while the pitcher is holding the ball, either you have a really long swing or you are a no stride hitter who takes a meaningless step before the pitch that makes you feel comfortable. Which would be fine by me. Just don't take a kid who is hitting like the clip and tell her she needs to get her foot down earlier. She doesn't. She shouldn't.