One of the great nuggets of interest I've seen over the years (not just with Aikido people; all styles) is that someone (usually a teacher) will be at a workshop and it is apparent to everyone there learning that the teacher simply has no previous skills in these things. In fact, often a complete newbie can do much better than the teacher. So there is an embarrassing silence while everyone simply works and progresses. Near the end of the work, the teacher has achieved a modicum of skill in some minor steps that are meant to be what he/she starts their new training on. Instead, the modicum of skill is turned into a "see, I already knew this stuff".... he/she and the students troop back home and continue working the same wrong stuff they've worked for years. Next time I see them.... no progress.
Ego is the biggest killer of progress..... and the years keep rolling by.
I see this at many (most?) clinics and seminars I've attended even at the level of the student executing the exact same error; usually the "my teacher teaches the exact same thing" sort of error and missing some important nugget of information due to the effort spent validating their existing training.