Hm, I would not call this 'The Lone Developer Problem' but maybe 'Future Comprehension Anomaly' wherein an author today understand their rationale for a design implementation but months down the line, it is as alien to them as it might be to a completely new set of eyes.

One solution is to leave meaningful comments that explain a thought process or design decision where it counts. This nudges future readers of the code in a direction towards total comprehension of the source.