I'm not a medical professional, or even much of an observer, so will defer to your expertise.
I saw a woman die on the 16th green once, probably for the very reason you describe. No defib at the golf course, and EMS was 15-20 minutes away. I don't think airports have a legal duty to have working defibrillators, but could be wrong on that point. Requirements for fire supression have a statutory basis, building codes, etc.