With respect to the architecture there are many attempts at addressing slow and error-prone builds with modular or 3D print methods. The savings is not a clear

With respect to the architecture there are many attempts at addressing slow and error-prone builds with modular or 3D print methods. The savings is not a clear win in all cases, however - it's not at the disruptive level we'd want(yet). There are also some material innovations taking place that ease the involved costs. Graphene has become available enough to be used in concrete mixtures for a substantial strength/weight improvement which can reduce material usage. On the streets, the big change going forward will be AVs and micromobility(e-bike, e-scooter etc.) - right now most cities are not Amsterdam, because they're locked in on the idea of providing space mostly for heavy vehicles that are unused 95% of the time; once you add AV rentals to the mix, it becomes substantially easier to cut down the size of the fleet, both in a vehicle dimensions sense and number of vehicles. This in turn makes it easier to use the lightest vehicles safely, so the streets will wear down much less quickly, even with no change in the builds themselves.