For specific building projects, cement is only made once before going into concrete for pours. And once concrete is poured into a building foundation, no further processing or transportation should be needed for that foundation for another hundred years or so if properly cured.
Plastics and other more recently proposed materials are still problematic. Even the longest lasting plastics will age much more quickly under pressure or with year-round solar exposure on the edges of a foundation. Many plastic ramps for auto repairs have collapsed, endangering those who used them. Production processes have have produced flaws. Construction workers wouldn’t always do enough to prevent solar exposure and other problems that would cause accelerated aging. Plastic production would obviously be too centralized (centrally controlled and regulated) and too often involves cancer-causing chemicals such as those in some of the furniture sold in Walmart stores.
https://www.atlasobscura.com/places/thomas-edisons-concrete-houses
Thomas Edison built some homes out of concrete using a one-pour mold. Most of them were pretty plain, but some of them were very ornate and detailed.
For awhile I lived about 2 miles from the old, abandoned Edison Cement Factory in New Jersey. I would mow my elderly neighbor’s yard and have a beer and chat.
After about the third time of him talking about him working at the Edison Cement factory and his various stories about “Tommy” it finally dawned on me.
“Wait - Tommy? As in Thomas Edison!!??”
“Well - who the hell did you think I was talkin’ about!?”