For what it's worth, this kind of behavior isn't limited to theory papers. Papers presenting analysis and model development also generally only show the "finished" result, omitting most or all of the bad models, training models, development models, etc. that were used to get to the final result. Same thing with observational papers in astronomy and related fields. There's a lot of work done that builds the authors' confidence in the correctness of the result, but that doesn't lend itself to a clean "story" for the paper or perhaps also ends up being supportive but not necessary to demonstrate a result.

I remember being surprised as a student, to learn that papers aren't narrations of the path to a discovery, but rather a narrative to describe the idea in a compelling (and hopefully clear) fashion.