Has such a thing happened in your country?
That’s hasn't happened where I live, but I live in a first-world country and I know of a case of sudden cardiac arrest that was miraculously saved. The person fell to the ground, and the person next to him knew how to perform CPR, while others called the emergency number. However, the first responders to arrive 15 minutes later weren’t the ambulance, but the police, and the ambulance arrived another 20 or 25 minutes later. In total, during 45 minutes people took turns performing CPR on him until the ambulance arrived, and miraculously, he’s alive and has no lasting effects. That happened in an urban area, not out in the middle of the woods.
On average, emergency services function better in first-world countries, but they have their limitations.