Without meaning to sound critical of our great layout creators (and they are all great!) it is too easy to become fixated with minor details, such as the track bed looking "too straight" or "too clean", or the rails "not dirty enough", etc. In the real world there would be an infinite range of possibilities just for the track alone, forgetting about everything else in a scene, while in the virtual world we don't have infinite storage space and processing power (at least not yet!). That is one argument against those conspiracy theorists who claim that the "real world" is just a computer simulation - aka "The 13th Floor" and "Vanilla Sky" movies.
Add to this, as dangavel points out above, Trainz assets, particularly splines, are limited to repeating elements of set lengths and "compromise, compromise" is the reality of route building. The "art" of route creation is in how we disguise those compromises.
My thoughts.