As a paramedic, somewhat. It's also to do with how -quickly- CPR starts. What -typically- happens (though by no means always) is the heart goes from a normal sinus rhythm to VT (ventricular tachycardia) to VF (ventricular fibrillation) to asystole / PEA (pulseless electrical activity) or similar.

Now by all means getting ROSC (return of spontaneous circulation) back doesn't mean everything is golden (indeed many patients re-arrest between home and the hospital), because we haven't fixed the underlying cause (plaque in the arteries, etc.)

But similarly, many younger or young adult arrests are often due to congenital defects or issues, diagnosed or not. We obviously don't fix that in the field either.

Where your statement is definitely much more true is in pediatric arrests. The vast majority of pediatric arrests are respiratory arrests that deteriorate into cardiac arrest - be it FBAO (foreign body airway obstruction), near-drowning, or similar. If we can fix the root problem - dislodge that foreign body (either by removal, or from the force of compressions), or at least allow enough air through, either naturally or by ventilation, to get to the lungs and re-perfuse the blood, we can usually get ROSC and, because we -have- "solved" (temporarily or otherwise) the root cause, those patients, thankfully, tend not to re-arrest.