The fundamental issue with this is that many problems have a time/energy/financial threshold for success. Trying to tackle such a problem with incremental iterative solutions will consistently fail, as each individual iteration will fail.

This is most obvious when network effects are present (e.g. local immunisation efforts vs country-wide immunisation), but it's surprisingly common in other government-related areas like welfare, childcare, social security etc.

Edit: Another comment has reminded me that affordable public transport is the perfect example of this: Incrementally building out a public transport system will almost always fail, as the initial lines (be they buses, light rail, etc) will typically not be successful enough to justify the cost of building the line. If, instead, a system is built out universally and simultaneously, the utility (and thus income) of each line increases due to the interconnected nature of the network.