We can't keep our roads in decent condition because we went all-in on car dependency. Roads are expensive, not just to build but to maintain, and every so often you have to rip them out and completely rebuild them which is at least as expensive as building them in the first place. The single biggest factor for "how fast does the road wear out" is "how many cars go over it per day." If everybody is doing everything in cars, then you need a lot of roads, and they're going to wear out relatively quickly, and once you hit a certain point, you simply cannot raise taxes high enough to pay for the road maintenance because there is just. so much of it.