George S. Ledyard
You might have different physical capabilities, maybe more or less athletic talent, you might be male, you might be female. You might be young or you might be old. But asking for a minimum commitment of time from all the students is simply asking that they, at the minimum, place their Aikido training in some similar relative place of importance amongst their other concerns. If they choose not to give it that level of importance, then fine. That is the choice everyone makes.
It isn't always a choice. There are people whose bodies will simply not let them train two days in a row. I'm one of these people, temporarily I hope, but for others it's a permanent fact of life.
If you wish to say that without a certain frequency of training, one will never achieve mastery, I wouldn't disagree -- you'd know much more about that than I would. What I dislike is the repeated use of the term "commitment", a word that encompasses both attitude and action, as if it were a matter of simple volition. This is only true for those who are able-bodied and unencumbered with responsibility.