Aikido has proven itself effective for many things. It has given me purpose and direction in my life, as well as made me a better overall martial artist. I have nothing to prove to anyone because I've witnessed Aikido techniques being used effectively by people that had a relatively low amount of training in the dojo. I've seen skeptical people humbled, as well as Aikidoka humbled by people with no formal training.
To be honest, Aikido reminds me a lot of Judo or wrestling...you have to have good timing and technique, because more often than not even a person with minimal amount of training will be able to resist a throw if they see it coming. You shouldn't be "trying" to perform a technique...it should mesh with the movement of their body and yours. Easier said than done.
Personally, I feel very few people have actually gotten to the level of say, true Judo or Aikido, etc. I know I'm not even remotely close. If I ever get shodan I still won't even be close. I'll just have a very adequate command of the basics at that level.