How do modern cars regulate temperature so well?

No one has considered the air flow under the hood either. There are modern automobiles that dont have a large grille to pull air through. There is so much shrouding under the car that air has to pass around the engine, then down the firewall.
Then there's the lack of temp range. They all come with a 195 degree thermostat. Water temp goes up to that and is controlled from 195 to 210. Difficult to notice such a small and brief change at the gauge. I see a slight needle movement right before the electric fan starts in my 96 Camry but that's because it has a bottle of Barsleak head gasket fix in it. I watch the heck out of that temp gauge. And BTW, that stuff really works in some cases. The worry never goes away.