"and they should have plummetted"

Again, Republican line of thinking that things should have occurred instantly and perfectly.  No one has ever argued that the ACA was perfect.  But it was certainly better than what we had before, and its for sure better than what the Republicans are proposing.

Obamacare has only been in full efect for about 3 years.  To expect to see hospital costs "plummet" in that short of a period of time, when people are still transitioning to this new system is unrealistic expectations.  There is no denying that hospitals have had to foot far less money than what they were paying out before due to uninsured patients.  Those costs savings come out to much more than just reduction in treatment costs - but it could be used to purchase new equipment altogether, hire more staff, or just keep the hospital running that much longer. 

Its not always about YOU, and what savings YOU personally see.