I'm sure they could have found someone in the EA ecoystem to throw them money if it weren't for the fundraising freeze. This seems like a case of Oxford killing the institute deliberately. The 2020 freeze predates the Bostrom email, this guy who was consulted by oxford said there was a dysfunctional relationship for many years.
It's not like oxford is hurting for money, they probably just decided FHI was too much of a pain to work with and hurt the oxford brand.
my near-completely data-less guess: frozen in 2020 among many other things that year that had sudden stoppages, no clear reason to get unfrozen after that, and then when their ties and batshit ideas got a bit too popular recently it became easy to drop them like a rock