Linux is "finished" in the sense that it works at least on some computers, in a stable enough way to let you do serious work. There is no computer in the world

Linux is "finished" in the sense that it works at least on some computers, in a stable enough way to let you do serious work. There is no computer in the world you could throw at the Hurd and expect your work to not get eaten by a grue. The HURD is an unstable POS and if it wasn't enough they change their mind every few years and switch their choice of microkernel to the fashionable kernel-du-jour. From GNU Mach to L4 to debate about Coyotos to someone who's working on Viengoos. In comparison, NeXT took the Mach microkernel, turned it into a somewhat monolithic architecture and made a commercially available OS, that was bought by Apple and is now on 10% of the consumer computers of the world. OS X is not the perfect academic OS but people are using it to do real work on it. Musicians, photographers and so on are productive with it. I expect that in 2020 people will still talk about the HURD as the Duke Nukem Forever of operating systems.