This seems like scare-mongering, or FUD, in my humble opinion. The reason that sewage and water is so hard to get right in the United States is in part due to

This seems like scare-mongering, or FUD, in my humble opinion. The reason that sewage and water is so hard to get right in the United States is in part due to sprawl, as well as the lack of political will to actually maintain infrastructure once it is built. A bit of a deflection I'll admit but - look at the NY subway. It barely receives the funding to keep basic maintenance afloat. Compared to equivalently sized systems in Europe it fails because there's a massive political diaspora to overcome since culturally taking transit is "for the poors" (you know what that translates to) and we can't be giving them anything. Similar holds true for sewage and water (for water, look at Flint Michigan). Housing, transportation, zoning, etc. are all the same problem. The reasons we fail at them are all connected and without taking a holistic approach we likely will remain bad at it. Pointing to any one thing and claiming "well even if we do that we'll still suck at 99% of everything else" isn't really a helpful description of reality, it just means there's more work to do. I guess what I would really push back on in your argument is the point that higher density requires higher competence. At some meaningless level, sure, we have engineers that have to solve harder problems. But the reasons that the US is bad at a lot of urbanist policies isn't because we lack competency (you could just hire people from overseas) - it's because we've allowed ourselves to build a system that incentivizes that incompetency at multiple levels through restrictive zoning, endless veto privileges a la "community feedback" / NIMBYism, car culture and the social disdain for what is perceived as normal in other countries (trains, bikes), etc. This isn't a problem with the US geographically or its people, and the problems have solutions. I think if you talk to most people in cities they probably agree wholly or in part on a lot of fronts, even if there's still a prevailing "got mine" attitude depending on where you ask.