It's not every vehicle. This is the 1st vehicle I had with extensive rust underneath. I've had vehicles with rust on the body, but not on the frame like this one. Looking back, I will say this, the first Runner I had, a 2000 Limited, was extremely rusty. Rear dif housing leak from rust, inner frame rail rust, not quite as bad as the OP. When that truck got rearended by a texting teen, the frame on the drivers side bent downward and cracked 1/2 up the outside of the frame rail right in front of the rear control arm mount. It was totaled and I actually got 200 more than I paid for it and bought my 99 Limited. This one was much less rusty, mainly because there was some very effective undercoating. I specifically remember power washing underneath and I hit the LCA cam eccentrics. One of them had the undercoating on it and when I hit it with the pressure washer it removed the coating and the eccentric looked brand new. There was another cam that wasn't quite as covered and was starting to rust where the coating was absent. I saw NO evidence of any kind of undercoating on my 2000. Moral of the story, if you buy new, it might not be a bad idea to get a professional undercoating done to preserve the carriage.
So it snows in CO right? What do they put down on the roads there?