Too much to maintain. They here and there. Such as a small project inside speced them out.
Most areas went to the nuclear exit signs. Even then it takes a guy months to document and replace when the time is up.
The problem with the EM lighting on a generator is it doesn't always get tested to verify the EM circuits are as plan after construction and remodels.
An example would be 1 breaker was turned off in a main service corridor, turning off every other light to save energy. Except that was in the EM panel.
Or a almost new hotel it was discovered many of the stairway lights were not on the generator after a utility substation explosion.
Despite the generators several hotels here have been closed by the fire department for being totally dark after an electrical failure.
The Paris, Rio, Rail Road Pass, Ballagio, Aria the ones I know of that were closed due to total darkness.