Any investment related to ET is probably not cost-effective, because there are probably no ET in our Universe (or at least not in our neighborhood).
Here’s my take on why: https://www.quora.com/Is-the-Fermi-Paradox-and-the-concept-of-parallel-universes-related-in-any-way/answer/Florent-Berthet.
Also, watch this excellent talk by Stuart Armstrong on the Fermi Paradox: https://www.youtube.com/watch?v=zQTfuI-9jIo&index=663&list=FLxEpt5QlyYGAge0ot24tuug
Many cost-effective interventions probably don’t work. You have to look at the probabilities.