1) We've more than doubled our population in the past 70 years which has allowed us to fund our current developments. This trend has slowed considerably and is

1) We've more than doubled our population in the past 70 years which has allowed us to fund our current developments. This trend has slowed considerably and is likely to slow even more. 2) Massive federal government investment in specifically this type of development. 3) state bailouts of failing municipal infrastructure. 4) we are already seeing it happen in the form of chronic under-maintenance: https://www.csis.org/analysis/united-states-broken-infrastructure-national-security-threat https://www.csis.org/analysis/united-states-broken-infrastru... > In Wisconsin, farmers are struggling to safely use modern equipment on roads that were built over 50 years ago. In Arizona, a century-old bridge partially collapsed last summer after a train derailed. In Florida, old pipes are leaking millions of gallons of sewage. https://www.cfr.org/backgrounder/state-us-infrastructure https://www.cfr.org/backgrounder/state-us-infrastructure > Civil engineers raise safety concerns as well, warning that many bridges are structurally deficient and that antiquated drinking water and wastewater systems pose risks to public health https://css.umich.edu/factsheets/us-wastewater-treatment-factsheet https://css.umich.edu/factsheets/us-wastewater-treatment-fac... > Although the lifetime of a sewer system (50 years) is longer than that of treatment equipment (15 to 20 years), renovation needs of a sewer system can be more costly. An EPA analysis estimated that if 600,000 miles of existing sewer systems were not renovated, the amount of deteriorated pipe would increase to 44% of the total network by 2020.