There have been second hand report of the current leadership at Ericsson saying that opensourcing erlang was the worst decision they had taken. As it would have given way a massive competitive advantage.
Nearly 80% of OTP development is and has always been, done internally at Ericsson. And they barely use the libraries from the outside world. From inside Ericsson, erlang look a lot like a proprietary language
There's pros and cons to these kind of things. "Best tool for the job" reasoned purely from a technical point of view isn't necessarily the "best tool for the job" when everything is factored in.
It's hard for me to judge one way or the other; I wasn't at Ericsson in 1998, or indeed, ever at Ericsson. I just figured that the language wasn't open source at the time and that they came back on their decision just a few year later were important bits missing from the previous comment.
Not necessarily… thst language clearly was a competitive advantage