Does it benefit Apple in any way?
Large scale? No. Software aside, Apple has a hardware problem... the M1 Ultra still doesn't beat a 1080Ti, so in that sense it's years behind. They need to up their game and introduce workstation or server/enterprise type of hardware if they want to play this game. The competition is RTX6000/8000 and at least A100. And once they manage to get close, the software kicks in. They can rely on 3rd party software like PyTorch and that might get better over time, but Nvidia knows this and they already reacted to this years ago.
On a side note, scalability might be another issue. I recently spoke to someone running a 4000 node A100 cluster. It's easy to use, for everyone. How do we scale macOS "servers" to that level? Slurm, OpenMP, ...?
As for Nvidia, they know there are alternatives to Cuda/cuBLAS/cuDNN, but is that really their focus these days? The past few years, Nvidia worked on other software. Omniverse with Metaverse applications took over and everyone who isn't focused on theoretical research will benefit from it. Those with robotic applications will use IsaacSim. Autonomous driving? Nvidia Drive. Genomics? Nvidia Clare. Medial diagnosis? Maybe Nvidia Kaolin. General physical accurate synthetic data generation? Nvidia Replicator. Digital Twins? A mix of all the Omniverse tools. There's literally something for everyone. Outside of that Nvidia eco-system, there's literally nothing equivalent.
Sure I could use CoppeliaSim instead of Isaac Sim for robotics and I do for teaching. Simply because it requires way less hardware and it's learning curve isn't as steep as Isaac Sim. Students can install it on their laptop for introduction level courses. Research and advanced stuff? Not so much. The same argument can be made for Carla vs Drive.
So in addition to much more powerful hardware and well supported software, they need these tool and I doubt they could rely on 3rd party (maybe open source) software for this.
For small home application and playing around with very basic stuff like cats and dogs classifiers, sure, that's an option.