Coming from a motorcycle perspective, tires are very important. This is because tire grip makes the difference between safe turns and stops and a wreck. Traction makes the difference between making it thru the snow or up a trail and being stuck.
I tend to trade tires well before the wear bar gets to the surface. Many may see this as wasteful. Probably the same folks who shop for tires by price.
For my 4Runner, each tire exchange is right at $1,000, and I tend to trade tires out at 50,000 miles. That's where the 2 cents per mile comes from.
Having tried a lot of brands and types of tire, I keep coming back to Goodyear. The P version and not the stiff E version. Silent Armor or maybe this time the Adventure All-Terrain. Both are top Tire Rack rated too.
Many here are holding out for the ATKO2. My poor road experience with the ATKO keeps me from that purchase. Since 90% of my use is on pavement, I demand great traction when stopping on wet roads, and grip when turning on rain slick corners.
Compared to road tolls, gasoline, or all the other costs of 4Runner ownership, spending 2 cents per mile for top tire performance is a good value.