Yep. And every day you hear stories of people getting fired from EDs. Wait, no. Most hospitals realize that they need the stability of the ED, as more than half of the admissions come from the ED. Which means more than half of the hospital's money. While it is easy for any contract to be released, the same is true for every speciality that works in the hospital. That means, cards, surgery, hospitalist medicine, peds, everything. Yet it doesn't happen daily like you're implying.
Not to nitpick the Ninja - who is usually quite on point...
While it is true that the ED accounts for a large percentage of admissions at most hospitals, the revenue it generates is highly variable based on payor mix and subspeciality coverage. In my shop, there are days that the cardiac cath lab alone generates more revenue in 8 hours than the entire day of patients seen in the ED. As a corporation, hospitals will always trend towards favoring and maximizing their highest and leanest earning specialties while attempting to "squeeze" their most resource-intensive departments to maximize their profits.
From a resource/benefit perspective, the ED as a whole is a loser for everyone but the physicians. Once patients leave the ED and get admitted, the specialist consultations and procedures reap benefits for the hospital. Indirectly yes, in some places, the ED can be responsible for over 50% of the hospital billing. As a free-standing facility, and depending on patient diagnosis, it is often a thorn in the administration's side.
As you consider the field of EM, think carefully about the population where you may practice (old/young, wealthy/poor, employed/unemployed, etc). Also look at the hospital and their specialty backup and volume. Hospitals that have a high volume of paying cardiac patients, orthopedic patients, and neurosurgical patients will often have a politically weak ED. It is in these instances where the administration may focus on the "loss" of the department and make changes.
However, as the new healthcare policy kicks in, ED's across the country will likely see a sharp rise in their percentage of paying patients, and this may cause many hospitals to reorganize their economic priorities...