You're assuming a lot by saying "there is no payoff".
For instance, you're assuming that if we get a signal, from aliens, we will learn absolutely nothing of value from it.
I think we've got a few smart people hanging out on Earth; more than enough to learn something valuable from alien signals. For instance, we might learn how aliens send radio signals, which might have some relevance to our own communication technologies. We might learn something about alien linguistics, which might have applications here on Earth that could be beneficial. We might learn what alien porn looks like, and I know that most of you reading this comment would be very interested in that.
What seems vanishingly unlikely is that we'd learn NOTHING of value.
For instance, you're assuming that if we get a signal, from aliens, we will learn absolutely nothing of value from it.
I think we've got a few smart people hanging out on Earth; more than enough to learn something valuable from alien signals. For instance, we might learn how aliens send radio signals, which might have some relevance to our own communication technologies. We might learn something about alien linguistics, which might have applications here on Earth that could be beneficial. We might learn what alien porn looks like, and I know that most of you reading this comment would be very interested in that.
What seems vanishingly unlikely is that we'd learn NOTHING of value.