This just doesn't seem like it takes probability into account. Getting someone to the hospital fast is almost always going to be better than waiting, and moving someone isn't usually inherently damaging if they don't have a spinal injury. In the context of a heart attack, it seems indisputable to me that it is better to drive if you have a safe and sober driver available.

It isn't all about getting somebody TO the hospital but getting them INTO the hospital/ED/ER. EMS in an ambulance who are alerting a hospital of an MI enroute will get their attention, a walk-in will have to wait unless there are obvious signs.

Calling 911 will normally get LEO on scene that know CPR and can do radio communications. A lot of dispatchers are EMDs (emergency medical dispatchers) that can start helping immediately. You may have off duty EMTs nearby that are scanning the radio. Finding a fixed target it much easier than finding a moving target (white car headed towards hospital), you are on your own if you get stuck in traffic. Statistically, 911/EMS is the best outcome. I agree with another commenter, exceptions do exist.