Agreed. If an exhibit is near completion already or significant in construction, I'm sure the zoo won't abandon that, but zoos that just started on these project may have to abandoned those projects.
Toronto was meant to open their orang exhibit this year, but it was meant to be finished in 2018 but kept getting postponed. Construction still hasn't started.
Consider that any exhibit (of note) that had been scheduled to open Spring 2020 began construction in 2019 or probably 2018. I expect the deciding factor in opening these exhibits will not be whether construction can be completed but rather more complicated issues of what zoo re-opening looks like and when the kick-off for a new exhibit can provide the best boost for attendance. Furthermore, delays in construction cost money. If zoo decides to postpone construction completion to "save money" it will cost them. But they can complete the exhibit and choose not to open it until it benefits them
