I'm not really picking anything, just sharing how it went with elixir in my org. I'm sure we could have done better, but the pit of success was not there for the polyglot teams. the elixir-only teams did a bit better, but mostly they just learned the ecosystem and then GTFO'ed out to greener pastures since they just wanted to write elixir and only elixir.
about your specific counterpoint, I think it's partially valid; I don't instantiate modules, I might not have named structs but just operate on Maps so I don't know the supposed module name, I might have misplaced the function in another module (while it's very intuitive to stick it to the object in oop)...and a million other things that are way too different for the average joe.