It's a little more complex than you present it. You only get to think of Alan as inefficient because you know what Charles did in a similar situation. However, if you only knew what Alan did you'd say he was smart and efficient.

He did everything he was expected to do and some more, a very industrious guy. He didn't seem bothered about doing a complicated design, writing lots of code, coordinating the other developers and the testers, revising the code several times and maintaining it. He wasn't lazy at all.

On the other hand, probably Charles didn't want to do all that stuff. He just wanted to write as little code as possible with as few bugs as possible and be done with it, no maintenance at all. And that required thinking very carefully and deeply about the problem he had to solve in order to get it right and write the necessary code.

In trying to do as little work as possible and return to Space Invaders, he had to be smart and efficient. That's the lesson here, great hackers use their brains and write great code to solve their problems with the absolute minimum amount of work required. It's really about laziness.