Avi K: Well, technically speaking, “No” is also an answer.
But, generally speaking, why would one think that their prayers would not be answered?
I think we too often get bogged down in a competitive view of the world (and what Chaza”l meant); it’s us versus them and only one team can emerge victorious (or, at all).
Isn’t it among the roles of the Jews to influence the nations of the world to accept HaShem as the One, true Master? If so, it seems imperative that, among other things, the tefillos of the non-Jews be directed to Him, alone.
I would think that if their tefillos are important, then a response of some sort is not an unreasonable expectation.