Let be honest here, who really use Erlang? How do you find people that knows this language?
Good languages attract good programmers.
The idea that we need to stick to popular languages is, I think, driven by business guys who want commodity programmers.
If you want 100 engineers added to your team in a year, then sure, use Java. But you will still be less effective, I bet, than 10 engineers doing erlang in that same year.
This will be a fairly small subset of developers, the ones that have motivation and time to put into growing themselves. So this probably means that the devs that know new language X are just more interested in software development (compared to devs that just know the language(s) they learned in school, and whatever they were taught on their jobs). So they have a much higher chance of being good developers.
You also use Erlang without even knowing ;-) Chances are every time your access the Internet via your smart phone, there is Erlang code managing that. RabbitMQ broker is written in Erlang.
A few well know companies in the healthcare world.