The problem is that WhatsApp really isn't just another CRUD app and it's very unlikely that you could pull off an engineering feat of that scale with a different technology. It is the exact counterexample of what you say.
The thing is that it is a CRUD app. You send it data (text, images or video) and get back data (text, images or video).
That's it.
It's not that different from Facebook.
Now, to get it to scale it may pay to use a high-reliability language. To make it secure you may not want to write it in C. But it would have taken off the same had it been written in Perl, PHP, Lisp, C, Assembly or Erlang.
That's it.
It's not that different from Facebook.
Now, to get it to scale it may pay to use a high-reliability language. To make it secure you may not want to write it in C. But it would have taken off the same had it been written in Perl, PHP, Lisp, C, Assembly or Erlang.
Maybe it would have needed more hardware.
Maybe it would have crashed a few times.
But it would have taken off nonetheless.