You are mostly accurate wrt. the "financial" situation of Scala.js. Except that the Scala Center has an explicit Recommendation to "ensure the continuity of Scala.js" [1]. At least that means that, should I (the Ph.D. student doing Scala.js right now) stop working on it, the Scala Center has a mission to ensure someone keeps working on it. As with all Scala Center Recommendations, this is not a guarantee. But given the popularity of Scala.js within the Scala eco-system, I am confident that solutions will be found! Read more about the Scala Center and how it works at [2]
It would be shocking if they hired anyone but the creator of Scala.js -- hopefully after you finish your doctorate this winter Lightbend and/or Scala Center will step up and make it happen.
[1] https://github.com/scalacenter/advisoryboard/blob/master/min... [2] https://scala.epfl.ch/