Why did the System V ‘{uchar,ushort,uint,ulong}_t’ types ever fall out of favor?

I always found them more aesthetically pleasing than the BSD-style ‘u_{char,short,int,long}’ types.

@winocm don't most people use uint8_t, uint16_t, etc these days?
@bob yes, but this is just more of a historical curiosity than anything else