“Where does it say you can’t give everyone a full stipend? I’m not finding that restriction in the NCAA announcement of the program.”
Because the number of scholarships is limited by the NCAA.
A team has 10 scholarships max. That means 10 tuitions, 10 room and boards, 10 books, 10 fees. And now 10 stipends.
You can slice those up into partials, but you can’t exceed 10. Paying 100% stipends to 50% scholarship students means you are paying more than 10.
Schools don’t have to pay any stipends at all to partial students. Although this would raise competitive and title ix issues.
You can pay partial students partial stipends. That’s what most schools are doing.
Paying 100% stipends to all partial students by definition exceeds the scholarship limits imposed by the NCAA in each sport. The math is the math.