Yes, of course, more and more hospitals are focusing on outpatient services, so that may have played a role in the decline. It could be argued, however, that a major reason for the decline of hospital in-patient admissions is less by design and more owing to the simple fact that people can't afford to be admitted.
And yes, of course, healthcare consumers aren't blameless here. Poor diets and sedentary lifestyles have done much to drive up the cost of care for chronic diseases like diabetes and hypertension. People have to take responsibility for their own health. Be careful, however, when throwing the blame at working- and middle-class Americans who toil for stagnant salaries while the cost of everything else goes up, who may not live in nice neighborhoods with lighted sidewalks, or who can't afford or don't have the time and energy for the gym when they're working two jobs or trying make a mortgage payment.