I'm the author. Thanks for the comment.

I agree with you, I don't know the Saleforce history but I'm quite sure that at the beginning of the company, they had lot of luck. I'm sure at least 10 other companies tried to address the same problem on the same market and failed.

Execution is mandatory but lot of the execution is also based on lot of uncontrollable parameters, hire the right guy at the right time.

Look at Evernote for example, they were almost bankrupt even if the execution was good, the market here and so on. It's a pure luck if the are still there and so strong.