If you want to change the way your home bathtub behaves, you have some options. You could, for instance, dig up your supply lines and install bigger supply pipes. This would give you more water pressure in the shower. On the other hand, you could install a more water efficient shower head to decrease the flow. Home renovation adventures might impact the operation of your bathtub, but at scale, infrastructure is often a last resort.
Consider a city with bad traffic congestion. In an effort to keep tax increases to a minimum, many cities will try to incentivize carpooling or transit use before expanding highway infrastructure. It is much easier to relegate a lane to ‘carpool only’ than it is to rip up the whole highway to add another lane. If you have ever lived in a city that has retrofitted its streets for rapid transit, you know just how costly and burdensome it is to solve a problem like vehicular bottleneck by adding even more transportation infrastructure.
The point is not that infrastructure work is ineffective or unimportant. On the contrary, there is little else that has more seriously damning consequences than poorly designed infrastructure. It is for this reason that building more infrastructure as a ‘bandaid’ solution to previously bad design often compounds and exacerbates existing problems. From a systems perspective, messing around with infrastructure is often considered a last resort.