“People with an issue this bad usually die within a year either from the pneumonia or choking.”
It depends...If liquids are changed to nectar or honey thick the problems are mitigated for a time. The esophagus in such nerve disease often lose their facility to handle thin liquids(saliva may become a problem as illness progresses) but thick liquids and solids they can continue to handle well into the disease state. Thin liquids mixed with food particles are a huge problem and is the biggest culprit behind aspiration pneumonia. Thickend liquids with food...not so much, at least in early stages. Also if the issue was caused by an old stroke, the condition may stabilize and improve over time or at least not get worse. Sticking to a dysphagia diet with thickened liquids, such afflicted persons do well over a long time.
Persons with progressive nervous system disease will have worsening swallowing issues until they are trached with a gastric feeding tube placed. Some may be okay without the trach but they’ll receive the bulk of their feeding via a tube for the rest of their lives.
If untreated or managed, yes folks with progressive dysphagia may pass away much sooner versus those whose swallowing and air way issues have been well managed. Such well managed persons may live out a normal life span!