I think of it like `success = (luck * skill)`. Meaning that if you have all the skill in the world, but the absolute worst luck, you can still fail, and vice versa, but with that said, the majority of possibilities for luck can be countered by higher skill.
Is Ken Thompson lucky? Probably was very lucky to have influences to point him towards electrical engineering and computer science, but with his level of skill, it's hard to imagine him not having a huge impact somewhere. Ending up at Bell Labs (let's say that's luck since he could've worked in a variety of environments) is definitely lucky, but he wouldn't have created UNIX if he didn't also have the skill. I think this goes for the majority of figures in computer science (I don't know enough about other fields to say that about them).
Is Ken Thompson lucky? Probably was very lucky to have influences to point him towards electrical engineering and computer science, but with his level of skill, it's hard to imagine him not having a huge impact somewhere. Ending up at Bell Labs (let's say that's luck since he could've worked in a variety of environments) is definitely lucky, but he wouldn't have created UNIX if he didn't also have the skill. I think this goes for the majority of figures in computer science (I don't know enough about other fields to say that about them).