You're mixing up capabilities with extra work with capabilities with no work.
If OS X also had tailor made kernel just for lower real time latency it could do even better.
But out of box, it's already better.
That said, the point is moot. 99% of pro audio/MIDI apps/VSTs don't run on Linux, so only experimental nerdy musicians and FOSS zealots would use it for real studio work. You do get the occasional profile on music tech websites e.g. "Techno musician X uses Linux", and somebody always jumps in a forum to say they use some Linux DAW (and usually add a list of ugly hacks, workarounds, and things that don't work), but it's clearly a total outlier situation...
Regular people aren't compiling kernels, they're installing something like Ubuntu Studio (https://ubuntustudio.org/) that comes with everything you need preconfigured out of the box.
If OS X also had tailor made kernel just for lower real time latency it could do even better.
But out of box, it's already better.
That said, the point is moot. 99% of pro audio/MIDI apps/VSTs don't run on Linux, so only experimental nerdy musicians and FOSS zealots would use it for real studio work. You do get the occasional profile on music tech websites e.g. "Techno musician X uses Linux", and somebody always jumps in a forum to say they use some Linux DAW (and usually add a list of ugly hacks, workarounds, and things that don't work), but it's clearly a total outlier situation...