Consider their situation:
Multiply the number of diseases/conditions by the average number of environmental factors multiplied by the number of genetic conditions which change how they present. The cross product is a MASSIVE search space and the ER doctors need to search it about 1-3 hours (on average).
Sometimes patients lie or mischaracterize their symptoms, leading to uncertainty about the data they get.
The emergency room is a triage center. For every bed that is full, there is back pressure into the lobby and out the door. Their job is to create a priority queue (or occasionally to turn into a triage center) based on patient volume keeping the highest average treatment quality possible, not to maximize treatment for any one patient.
Symptoms alone aren’t always determinative. Many flu-like viruses present with almost the exact symptoms, despite being different viruses and having different impact on the body. The ER may discharge you before the labs come back with a positive identification of the exact virus strain, meaning it may be way more dangerous than the seasonal flu, but they play the odds unless you have known comorbidities.
Even if the doctors make a mistake in the ER and discharges you, there’s a decent chance that will live. The body can fight off many diseases by itself (without doctor’s intervention) and if not, there’s a chance you can make it back to the ER for a second attempt. An ER’s job is to keep you alive during your visit to the best of their knowledge, not to see you through the entire course of your disease. As discussed in the article, there are a shortage of hospital beds in other departments, so Ears end up being a poor stopgap for those.
Chronic diseases became more common as doctors and medicine increased our lifetimes. ERs are not the right place to manage chronic diseases, but it’s de facto where the indigent go for their only health care access and where acute issues related to chronic conditions are managed.
People need massively more hospital care during their last year of life and boomers are going through that time of their life. Hospitals are businesses, so they are min-maxing their capital outlays (how many beds they can support) with equipment and staff. If they overspend, they have to charge more than the already outrageous prices they have. If they underspend, some people will get undertreated and hospital staff will get overworked, but that seems to be acceptable to American society, so that’s what we get.
Medical science isn’t perfect. It doesn’t have infinite resources to investigate every possible condition. You couldn’t afford it if they decided to do every diagnostic test possible.