This gets overlooked.
In San Francisco, if I count the number of jurisdictions I fall and pay taxes under, I get a number like 7, the typical City/State/Federal tier (minus the County tier as SF is unique in CA for consolidating that into the City tier), and at least 4 special districts that are just the ones I can think of off the top of my head.
Singapore is 1 City 1 Nation. I’m not an expert on precisely how they govern themselves, but it must really help cut through administrative overhead and bureaucracy when the national government is effectively also the local government, responsible for police, fire, the environment, the parks and playgrounds, utilities regulation and national defense.
So if they want to set aside a line item for city cleanup right beneath national security and the public healthcare system, they have the option without debating further past public/private for whose responsibility it is. The government can take the tact that it is either its responsibility or it isn’t, without the complex tax system imposed by several different entities that the US has getting in the way. No federal grants to grant, no support legal challenges in 50+ court systems and various appellate court districts to overcome, no multi-tiered incentive structures, just, “do we have the budget?”
There are certainly more advantages to be had for larger countries, but there are also certain quality of life advantages to not having to be a large country, as long as you are rich anyway.