I wouldn’t presume to suggest, from my arm chair, that “this is why you didn’t run faster” because it’s almost always a multi-faceted reason rooted in programming in general.
That said, based upon what you’ve written only, I think you answered your own question.
There’s only so much tolerance for CNS intensive work and that capacity is unique to each individual. The higher your output potential for any particular CNS intensive component the more careful you must be when programming that component into the overall plan.
As for the weight training, what I see so many individuals fail to accept is that maximum strength is improved with sub-maximal loading; however, it is only realized to its utmost via the performance of near maximal loading. This is why only the actual strength athletes need perform, on the whole, the highest percentage of near maximal lifting because they won’t perform to their true maximum on contest day unless they perform the proper stimulatory sessions with higher intensities subsequent to the meet.
Now, there’s also the question as to whether you were even competing in the right event/sport relative to your morpho-biomechanical potential.
One of my biggest criticisms of the US sport system in general is the lack of sports physiology knowledge possessed by every profession encapsulated within the coaching industry. For example, if you’re strength/explosive strength, short accel were your strengths, and not your maxV, than perhaps your true potential lied in one of the throwing disciplines (I don’t know how tall you are/limb length though), bobsled brakeman, American football back, Rugby, and so on.