If [awesome library] is the primary thing your code does, then sure, you might be stuck with [language X]. But if it isn’t, then perhaps the [language Z] replacement might be good enough (or better but not yet well understood, as in the case of the OP), or you might keep [language X] just for that small component.
And that's why I keep [language X], because sometimes the equivalent in [language Z] is not as good.