It might be crucial to keep the Arecibo telescope around. While there are newer, more advanced telescopes (such as the Atacama Large Millimeter/submillimeter Array), Scientific American notes that Arecibo's giant dish is particularly well-suited to finding gravitational waves and pulsars. Lose it and you'd suddenly have much less data.

There's also the simple practical concerns. Shutting down the telescope would be expensive: completely restoring the Puerto Rican landscape is estimated to cost $100 million, or more than 12 years of operation with its current budget. And that's excluding the economic costs to the community around the site. Although it'd be unrealistic to keep Arecibo running indefinitely, it's possible that business as usual would be both cheaper and smarter.