it sounds like you are asking why enterprises aren't choosing to write Rust code vs Java code. I wouldn't turn away a developer just because they had experience with Elixir.
It really comes down to whether there's someone making the case that a particular application/subsystem has specialized needs that would warrant hiring experts, and whether they can make the case successfully that the system should use technologies that would require additional training and impose additional project risk.
Until you are dealing not with enterprise applications but actual services, it can be difficult to even maintain development teams for maintenance - if your one ruby dev leaves, there may be nobody keeping the app running.
Even when you are producing services - if they are monolithic, you'll also be strongly encouraged to stick with a single technology stack.
No, I was making a point about if the goal is lowering resource usage, more throughput, concurrency, speed/perf, etc, a larger company can achieve that "unfair advantage" of things like rust or elixir etc because they have the resources as compared to SMBs or startups.
Of course, every company and org has to see whats best and feasible for them. Valid points you brought up no doubt.
It really comes down to whether there's someone making the case that a particular application/subsystem has specialized needs that would warrant hiring experts, and whether they can make the case successfully that the system should use technologies that would require additional training and impose additional project risk.
Until you are dealing not with enterprise applications but actual services, it can be difficult to even maintain development teams for maintenance - if your one ruby dev leaves, there may be nobody keeping the app running.
Even when you are producing services - if they are monolithic, you'll also be strongly encouraged to stick with a single technology stack.