Is the loss of Arecibo a big blow to the scientific community? I was of the impression that Arecibo was long past it's heyday and in general that large arrays of smaller receivers were now considered superior.
I've mentioned this in a previous comment [1] so I won't rehash it again, but here [2] is a statement from the NANOGrav collaboration - we have been using the Arecibo telescope on a weekly basis (along with the Green Bank telescope) to observe a large number of radio pulsars for over 15 years now, and when we announce the first detection of very low frequency gravitational waves, Arecibo data will play a critical role.
This loss really hurts. The US community is scrambling, and we are going to have to rely on the generosity of our international partners going forward - there's just not going to be enough telescope time to do all the science that we'd judged as very important through competitive review processes.
(And that's before we get into the unique radar capability, etc.)
[1] https://news.ycombinator.com/item?id=25154898 [2] http://nanograv.org/announcement,/press/2020/12/02/Arecibo.h...