Well, the world before MMA says they would. They did. The Gracie's ran ham on everyone for a very long time. When bjj finally came to North America with the initial UFC's, for years many people wrote off pure boxing/striking as useless. Now we have people that are proficient in everything, and teachers and examples of striking that are modified and aware of the ground and what to do there. Wider stances, more protected legs, different weight distribution and movement.
And striking is better for it.
Boxing brings an element to fighting, the same as bjj does, but sometimes one pure element can trump another. I do not train aikido, and from what I've seen the vast majority do not train it for sparring or fighting, but I've also been exposed now to some that do. Aikido too, can add an element.
Even if pure boxing beats pure aikido every time, the man that is equally proficient in both will beat the boxer.