Takeda, Ueshiba, Sagawa, Mochizuki.....all prided themselves on MMA. Were they alive..they would be more current than most everyone. They would pursue modern combatives...and still have IP/ aiki.
From what I know, they loved to cross train.
If they were alive today they would have a study in every style that would come back and teach them.
IMHO, it wasn't the style but the type of men they were that makes the difference.
Perhaps because we are different types of people, we are not doing the same Aikido?