Gentrified western economies have economic growth of around 2% on average. Developing countries moving from mostly rural or controlled economies to market indus

Gentrified western economies have economic growth of around 2% on average. Developing countries moving from mostly rural or controlled economies to market industrialized economies can, and do, have growth of around 10% or more. That's a fairly big difference in available funds for capital projects. The same way the US was building trains in NYC, Chicago, etc 100 years ago, China and others are doing so today, but with the advantage of globalization, automation, and mostly solved technical issues for even advanced systems. Essentially, the point at which your society hits this growth really is going to determine the what kind of infrastructure you're stuck with. The big exception here is being bombed to the point where you have to re-do your infrastructure, which is the case with Europe and why they tend to have newer mass transit infrastructure than the US which saw no bombing on its homeland, and of course has the added problem of a huge homeland which makes more sense to fly around in, than ride around in. A good example of this in tech is how the US pioneered DSL (Joseph Lechleider at Bellcore) and how quickly the US telcos ran with it. By the time the Europeans and others caught up, DSL had advanced to ADSL2 and ADSL2+ which gave 2x to 5x the bandwidth. Meanwhile, US subscribers were stuck with vanilla DSL for decades because the cost of upgrading was so prohibitive. There's a problem with innovative countries where they run with revision 1 of some new tech, but then are stuck with rev1 because big infrastructure changes take a long time, and you can expect decades of use before replacement. Or in the case of trains, centuries - the CTA in Chicago is built on tracks originally laid in the 1860's. From a tech perspective its weird to think Chicago was running light rail before homes even had electricity. Waiting until later revisions to build out your infrastructure, either intentionally or not, comes with fairly big dividends. Now is very good time to lay down infrastructure due to all the computing power we have, automation options, lowered costs via globalization, and focus on renewable energy. That said, infrastructure improvements happens as needed in older economies. The US has an impressive air system, for example, with at least 75,000 flights per day and at relatively low price points. We've probably hit the efficiency and feature maximum with jets as-is, so not much room for innovation here, but its clear for the US, air became the focus instead of trains. You can fly from Chicago to LA in 4 hours. Even a 'fast' bullet train with zero stops would take 10 hours, most likely closer to 15 with stops. Also, air is privatized, so there's no worrying about raising taxes or cutting social programs to pay for a subsidized train expansion, which would take quite a bit political will from taxpayers, most of whom are happy with car ownership for daily commuting and airlines for longer trips.