An easier example is Git. If Git wasn’t made. Or perhaps it was made by an unknown and thus didn’t gain traction, the world would be pretty close to how it is now. Another DVCS like Hg would’ve been widely used or a split of a few. However it would’ve ended up, the world would be, relatively speaking, the same.
We'd be all on win :((((
Joke aside : BSD would probably at it's place - one thing that we could advocate as being unique to unix is it's viral open license system
GNU is not Unix
Linux was available now. Hurd ... was not. Still isn't.
Hurd is based on a microkernel architecture, which was/is enticing because (quoting https://en.wikipedia.org/wiki/GNU_Hurd ), "In theory the microkernel design would allow for all device drivers to be built as servers working in user space" and "According to Hurd developers, the main advantage of microkernel-based design is the ability to extend the system: developing a new module would not require in depth knowledge of the rest of the kernel, and a bug in one module would not crash the entire system."
There is a long debate about microkernel vs monolithic kernel. See https://en.wikipedia.org/wiki/Microkernel for one such summary.