Moribund
Etymology
From Latin moribundus, "dying," from mori, "to die," the same root behind "mortal" and "mortuary." It entered English in the eighteenth century first in the literal medical sense of a patient near death. It soon widened to institutions, customs, and enterprises that are fading toward extinction.
adjective · /MOR-uh-bund/
At the point of death, or so weak and stagnant as to be near its end.
What it names
The word for something visibly dying out — a moribund industry, a moribund tradition — kept alive in name but drained of vitality.
Example
By the time new management arrived, the once-great newspaper was moribund, coasting on subscriptions from readers who no longer read it.
Related idea
Obsolescent means falling out of use because something better has arrived; moribund means dying of sheer exhaustion or decline, whether or not a replacement exists.