Yes of course, I just would have assumed the cost of that is pretty minor compared to the cost of the (apparently) 26 megawatt cogeneration plant
If the system wasn’t designed for the switchover from the beginning, I can see how it would be considered impossible/not practical to do. Especially when this type of “blackout” was thought to be rare.
I’m sure the prior assumptions would be reconsidered today.
Not many? As in, I don't think many buildings would have two separate power feeds. I'd expect a small number of very large connections from the cogen plant and the outside word into local distribution network(s), and then everything is single-path from there on.