[posguy]

Architecture emulation like QEMU provides is commonly used, just a matter of how much investment is made into backwards compatibility by those who build your operating system/platform.

Apple works hard to break backwards compatibility every few years, while other operating systems will happily run software from decades ago as they care and invest in not breaking userspace.

[yagya]

Apple really likes being on the bleeding edge of computers, and it often comes at the cost of older programs and features being killed off in that process.