I don't doubt that aikido training can have real self-defense benefits. But an aikido student is going to spend a lot of time learning stylized techniques and practicing them against stylized attacks, training with and against obsolete weapons, and trying to preserve O Sensei's tradition. Someone who is only interested in efficient, effective self-defense is going to find a lot of things in the average aikido class that are irrelevant to his interests.

That doesn't mean that this theoretical person is wrong for wanting what he wants, or that aikido is wrong for not providing it. I just think the two could find more compatible matches than each other.