“Ever tried. Ever failed. No matter. Try again. Fail again. Fail better.”
The message here is quite simple. This is not purely to make it understandable for the common man, but instead being a common relatability to the sentence in order to make it relatable. He is trying to make the point the regardless of failure, there is always something to be learned from failing again. Failure in this case is the absence of perfection and only through the not achieving that will you truly find your completion.
The sentence structure is very pointed and clear. It makes me think like an old man is imparting a life lesson rather than it being an exercise in human understanding. I envision my grandfather talking to me and only me rather than a random disembodies consciousness of an author giving me lessons from on high where I cannot see.
Changing the sentence would drastically change the readability. A DC IC format would result in a much less structured tone. Rather than it being a clear message to try harder and learn from mistakes it becomes very ambiguous and flowing. It could almost flow right into the oblivion of the next sentence. As far as not adding question marks, their absence makes the sentence feel much less passive. With them added it would see a much weaker tone. Generationally it would not feel like the language of the author and would therefore lose credibility.