Because we write extensible instead of composable software. We do not distribute functions, but apps.

How many instructions do you need in assembly to compute `1+1`? How many instructions do you need to open your search bar, get the calculator and do the calculation?

We also make software responsible for way too much. Cross-platform is a joke. How can we expect developers to consider every platform? Obviously they will switch to some other magical solutions that promise support (and deliver overhead)

Software lacking composability also mean that if the developer doesn't provide a feature, users will most likely never have it. It is therefore encouraged to over-feature everything in case somebody somewhere want it.