I'd rather speak for myself here if you don't mind:
I'd like to point out that most car users do not really know the performance parameters of their cars. Much less be able to name all the components in the car which work together to keep the car running.
Same goes here for computers.
Sure, you can go ahead and worry that your computer runs 1C below maximum recommended. You'd just be wasting your time. The average computer user would probably rush here if they found out their GPU was running so hot it could boil water... but some GPUs have been designed to run at those temperatures.
The average computer user, who doesn't notice anything wrong with their PC, would spend money to cool down their PC. Fewer still would do so if you told them its gonna last 20 years without a problem anyway.
The only reason why you'd build a nice "'32 Ford 5 window with a 350 under the hood" is because you are a car enthusiast of some sort. Same goes with computer enthusiasts, we monitor our temps all the time.
I personally know what temps my computer usually runs at, and if it deviated by 2C, I'd have it cleaned immediately. But I also help people out with their comps, and just advice them to clean it out (software and hardware wise) if they noticed any problems with their comp, without even asking temps.
You are obviously and enthusiast, so I wouldn't be surprised if you knew your computer temps, maybe got an icon, or an LCD on the case which tells you its temps real time.
Maybe you've even got another probe stuck somewhere on the heatsink (right next to the CPU if you really knew what you were doing) to measure out the real temperature of the CPU. And you would have done that, since you knew that any other form of temperature testing would have been useless, since they aren't accurate in any way (please don't start with all the bs about BIOS temps and software programs, or those 3.5" temp monitor things. If you DON'T calibrate on a daily basis, it can be as far as 10C off the real temp. If you're lucky).
Still think everyone needs to know their temps?