Is Elixir the Best Tool for a Startup?

I would say if you want to build really functional programming oriented front ends, you should probably look at Elm. I have a mixed relationship with Elm, but it feels very clear to me that react plus type script is just an attempt of doing L. At least it seems like React is shifting away from class based components and into functional components. But yeah, JavaScript is iffy at best as a functional language. It really, really allows you to break the functional aspect of it.