Steel pipes are used in a variety of applications. The ones that might come immediately to mind are water and sewage. However, they are also used for lightweight but strong structural support, scaffolding, oil and gas pipes and other industrial applications.
Steel pipes or tubes are directly responsible for the creation of super tall skyscrapers. This came about in the 1960s when the advent of steel tubes for structural support revolutionized engineering and architecture. It had been a few decades since the world had last seen a building frenzy of skyscrapers. This development fostered a new building frenzy as architects and engineers took to structural steel tubing like a kid to a new toy on Christmas. Thus, all of the tallest buildings in the world today simply could not exist without steel pipes. This includes The Twin Towers that were destroyed by a terrorist attack on 9/11. Cityscapes across the globe would look different without structural steel pipes.
They are also integral to scaffolding. Scaffolding would still exist if there were no steel pipes, but it would be more cumbersome, heavier and not able to reach as high as it does. This would significantly impact renovations and clean up projects on multistory buildings. Again, our cities as we know them today would simply not exist. Buildings that currently get renovated might simply get torn down after years of slowly deteriorating. There would be a lot of history lost in the process, as well as substantial functionality.
Lead water pipes were common in the U.S. until the 1950s. For health reasons, their use fell out of favor. Thus, most American homes built in the 1960s were built with steel water pipes. Steel pipes were safer than lead and cheaper than copper. Plastic pipes were not yet in common usage. These days, plastic pipes are a commonly used, cheap alternative to copper water pipes. Thus, the postwar housing boom of the 1960s would have looked different if affordable, safe steel water pipes had not been available. Back then, the average new home was substantially smaller than what we see today and lacked a lot of amenities that are taken for granted now, such as air conditioners and microwaves.
Housing was more basic, thus, there were fewer ways to cut costs. If steel had not been available when lead stopped being used for water pipes, a lot of houses might simply never have been built at all. Whatever housing crunch we currently have would be far worse.
Since homeownership was such a cornerstone of financial security, many solidly middle class families would have not existed. Many of the kids that went to college because their parents bought a house and achieved a certain level of security would not have had the same opportunities. The entire socioeconomic landscape would look different in some way without common, affordable steel water pipes in American homes.
Things that are as common are often taken for granted. But, they are the foundation upon which our world is built.