[gingerBill]

Because to be _standard_, it would have to come with the compiler toolchain. And if it's scattered around on the internet, people will not use it.

I tried to create my own alternative about a decade ago which eventually influenced my other endeavours.

But another big reason is that people use C and its stdlib because that's what it is. Even if it is bad, its the "standard" and trivially available. Most code relies on it, even code that has its own standard library alternative.