The current script I'm working on spans the entire life of the protagonist.
Is it essential that the theme of the story be present in every scene? No
Is it wasted story telling if you are showing how the person got from one point to the next if doesnt incorporate the theme? No
Thanks for any help!
Theme is not the same as character arc or story arc. You are showing how the character(s) come(s) to believe or act in a way consistent with the theme. Though initially or in the middle they may act or be quite the opposite. The theme becomes evident by the final scenes.
Being heavyhanded and telling the audience-"Duh, this is the theme" is a sure way to alienate the viewer. An example is the spiderman series where they drill repeatedly into the audience about choice and responsibility. While others may have different opinions, theme should become apparent and evolve from the story and the character dynamics, and not vice versa.
For instance, let's say you are doing George Washington's biography. If every scene has him telling the truth and being heroic, it may be true to your theme but the character becomes very predictable and one dimensional. If you present him with situations that cause conflict and he falters at times but makes amends later, the audience sees him a human and overcoming obstacles. You might also have scenes of when he's not in conflict or satisfying the theme.
Transactional analysis discusses "slogans" which are kind of life themes people live by. Doesn't mean every waking moment we are acting on it, but it is an overarching way we organize our lives. Most themes are ideas we already know, so being too in your face comes across as preachy and moralistic. And, as with spiderman, can detract from an otherwise enjoyable movie.
If all the protagonist's life they've put others first, and in one fit of anger they put themselves first, it can be a growth experience. Now any future selflessness has a deeper personal meaning. You can't grow if you don't occasionally step outside of the norm, breaking the theme or slogan.