Earlier quoted context omitted.
Writing something in PHP made sense in 2004. Although Erlang was around at the time, it wasn't at all well known. And no, you are not absolutely right, Facebook is not a PHP (only) shop. Their chat backend is in Erlang and that's a much bigger tell-tale than their legacy code. Also, a lot of us Erlangers speculate that Facebook bought WhatsApp (not only but also) because of their huge infrastructure know-how and (Erl…
Isn't that argument bad for erlang? That you need to pay an atrocious price for erlang know how.
That erlang know-how commands a high price on the market is a good argument for developers to invest in developing that know how, and for organizations to work on fostering it in their staff.
Its only "bad for erlang" if you assume the only way to adopt erlang is for an organization to wake up out of the blue one day and decide "from this day forth, all our work will be in Erlang, and we're going to go out on the market today and hire up Erlang talent to enable that to occur."