most fancy designs might require technology that our contractors might not have. (and will be expensive acquiring them for one project)
so achieving the exact design during construction will be hard.
some people don't want to stand out, so using the same design helps blend in with the surrounding.
most of the major works will be given to the veterans in the industry who are old and not open to new designs.
the fancy designs are also expensive to build especially when it comes to concrete and reinforcement. (which are the major construction materials we use here)
but we are slowly adopting flexible construction materials like the EPS, containers, prefabs..... so slowly we might have new modern and fancy designs.