The Apple That Cannot Be Shared
Although Apple designs the Mac, you cannot legally run its powerful operating system on any other brand of computer. Apple keeps this software exclusively for its own hardware lineup.
This strategy creates a strictly closed ecosystem that distinguishes Mac from the more open world of Windows PCs. Because the software is fine-tuned specifically for Apple's proprietary hardware, it achieves a unique level of stability and efficiency. By controlling both the physical machine and the internal code, Apple ensures a consistent experience that competitors cannot replicate. This tight integration has defined the brand identity since the very first Macintosh arrived in 1984.
Source: Mac (computer)