There are much more good programmers out there than break away products like WhatsApp.
You can't create successes like WhatsApp just by hiring good programmers. There are plenty of great teams that didn't achieve product/market fit and failed.
There are plenty of great programmers at Facebook or Google that do important but not wealth creating work (not on the scale of WhatsApp wealth).
In cases like this most likely the reason why WhatsApp is popular is that there was a person in charge who had the right vision for the app and came up with just the right set of features and a little bit of luck.
But even that person isn't valuable per-se in the sense that you should hire him for your company at all costs hoping that he will create similar wealth for your company.
I'm sure I'm butchering the analogy, but those are Schrödinger's successes: you can only tell they're successful at the time of the exit, but not at any time before that.