. At 100% power, your life expectancy on the road would be measured in minutes if not seconds
Quite far from it. Over here we don't have a speed limit and there are still ways where you can drive at max power for considerable amounts of time. Not hours nonstop of course, but rather run it for half an hour at max, then brake down to low speed (120/140km/h) and then accelerate back to top speed again. This is actually quite demanding on an engine, lots of power changes and due to constant reaccelerating quite often full power demands.
However sadly many if not most manufacturers have a buildin speed limit, most of the time measly 250 km/h, some a tad higher (my last car had 270 km/h). Sadly at that speed the engine won't produce max power, only around 65 to 85% depending on size. Of course that doesn't apply to those small cars some like to drive. Modern car engines engines are pretty steadfast, in fact most diesel engines are used as the core in small powergenerators (Blockheizkraftwerk in german) that are used to power and heat a home or several homes. In those they have to run permanently for at least 10 years without major problems.