But isn't that what we want? Would you prefer that e.g. bridges used custom hand-crafted screws in weird diameters instead of standardized, cheap, proven off-the-shelf parts?

Everyone doing their own non-standard thing is e.g. why international train travel in Europe sucks. There's 6 different voltage/frequency combinations for high-level rail in Europe alone and dozens more for local systems. There's more than 20 incompatible train control systems as well. Running an international train service might require changing locomotives on every border crossing, because of garbage like that.

Standardization is a good thing.