Realize this...the only thing between you and the road is your tires. The wider the tire, the more contact you have with the road. However, more contact means more friction giving you better traction in dry weather for improved handling, but you can't go to much bigger or wider without hitting wheel fender while turning. The weight of the car is also distributed over a wider area. More friction means your car works harder meaning you use more gas. All the roads are also an even grade with no hills and there are no head winds you might drive into while stopping at all the stop sighs and red light. Also the weather really does not effect it either. Never mind all the people I see driving with under inflated tires in the first place and have a really heavy foot.
However, when roads are wet, you have hydro planning and since wider tires distribute weight differently, you will hydroplane earlier with wider tires than narrower tires. Furthermore, for someone like myself living in the norther climate where snow falls in the winter, those without AWD or 4WD usually consider slightly narrower tires during the winter so that more weight bears down on a smaller surface in hopes of giving them better traction when there is snow on the ground. It being colder out, the tires won't over heat as quickly, and that does not mean it can not happen.
That being said, the larger the vehicle and the more weight it has should not put a tire that is to narrow on their car as they will probably wear sooner or as I have seen, blow out from over heating on the highway anyways from to much weight being applied to a narrower surface area.
Some cheaper brands wear quicker and you have to replace them earlier. More expensive ones obviously and hopefully last longer. To a point, like BMW and Mercedes, your paying for a name because they spend more on testing like yokohama, perelli etc...
