In the past, you might have automotive-grade microcontrollers for functions like ABS, which consume less than a Watt maximum. You paid a little attention to having enough ground vias on the PCB for thermal conductivity, and that was about it to qualify the design for the high end of the temperature range.
Degraded lifetime wasn't so much of a concern.
These days, you've got ARM processors with a TDP of 15W or more, and keeping the die temperatures below the maximum when the ambient temperature is 85C, well, that starts to get interesting. Especially if you don't want to use a fan, and the processor is stuck somewhere without adequate airflow.
And then you've got high-end systems with a TDP in the 150W range. Then you've got to have a good cooling solution to run your application at office environment temperatures, nevermind the full automotive temperature range. And what's going to be the lifetime for these parts running at elevated temperatures, even if you are staying within the maximum temperature limits? Sigh