> (1) even after large libraries support 3 there will still be a long tail of libraries that aren't ported (and will never be)

That should be a non-issue unless you require one of those libraries.

> There's no must-have feature for us to justify that effort, so we won't be making the switch for the foreseeable future.

There's no reason for making the switch if you're going to ditch your code base in the foreseeable future. Otherwise, you'll have to justify your decision in the unforeseeable future. And thereafter.