From a side view perspective any deviation from the lunar plane would be a distortion of the straight line. As long as the flight path remains on the lunar plane then it is correctly represented by a straight line.
That is a truly epic fail of an observation. The TLI flight path was 30 degrees to the ecliptic plane. The lunar orbit is inclined by 5.1 degrees and the only relevance this has is where it intersects the transfer orbit. Apollo flight paths are Earth orbits, as are the Orion.
Sadly for you that is all they have in common. The eccentricity of Apollo took it around the weaker areas of the belt and took it out to a path that intersected the Moon. Orion was only eccentric enough to allow it to travel through the inner belt.
How in heavens name can you say they are the same? They are completely different.
The most fuel efficient path to the moon is to place the craft on a lunar plane and then fire the TLI rocket to extend the circular object into an elliptical one that intercepts the moon. any other path would require multiple stages to correct the misalignment.
Saturn V had multiple stages. What's the problem? Oh, I know, you think direct ascent was the method.
And fuel efficiency was not the only mission goal, other things like survival of the astronauts was also a mission goal. Do you really think that NASA would say "**** the astronauts, this will save fuel"?
Well, maybe on planet sausage they might. Not in the real world.