As I said in our earlier piece outlining how perhaps SETI had outlived its usefulness given modern knowledge, the success metric was that a civilization more than 400 years away - because we know there are none closer - would have to have sent low-tech radio signals to a planet that lacked the technology to receive radio signals when they sent them. The aliens basically would have needed to know the future, which means they didn't need radio waves.

They cited inadequate government funding as the reason for the shutdown but, really, this thing shouldn't be government funded at all.  If Paul Allen and Jodie Foster and other rich people want to fund it, and they do, that is cool, it just isn't science.

Writing at TG Daily, Starr Keshet has a different take on why SETI is a waste of time - namely that we're too goofy as a species to have alien civilizations want to contact us.

Though the idea that alien civilizations will be less goofy is an awfully anthropic principle concept, Keshet may have a point, as the popularity of Lady Gaga can attest.