That does seem like the same arguments that are made prior to just about anything becoming mainstream though. I'm not saying it means nothing that python has so much mindshare, but the same could have been said to pythons predecessors as well. You're right about commercialization not being about technical excellence, in the short term. In the medium and long term, it's the advantages of recent technical excellence that drives a lot of commercialization.
It's also the same arguments that are made prior to things falling by the wayside.
Not that I think Elixir will ever fall away, just that it won't go fully mainstream.
Unfortunately it is a popularity contest, where entrenched network effects are working against Elixir.
As a Python programmer, I truly believe Elixir/Phoenix is the best stack out there from a technical perspective.
However the incredible breadth of libs and resources ... and most importantly the mind share (both available devs, but more importantly available jobs for seniors who commit to Elixir) means that it is still just not a competitive choice.
Almost all commercial software dev is not about technical excellence, but rather about applying the available tech to a particular business domain. And there Python (and .Net, Java, PHP, Ruby ... even Go) are so far ahead that sadly Elixir doesn't look like it will make it.
I don't know that anything can be done about this. For all that I think Elixir is better, I, like most devs, am not about to sacrifice (or even impair) my career for the cause. Personal remuneration wins out.