Whatever Microsoft offers. Or occasionally Linux. Which are usually considerably better than the support lengths Apple offers. For example Windows 7 was supported for over 10 years, 8/8.1 for over 10 years. They also don't tend to sell the same model for literally years.
Linux is a totally different story. “Linux” doesn’t support anything. It’s a kernel and doesn’t remove things out of tree so comparability is rarely removed so you could build things. But user space / distros and binary drivers can be a different beast (DKMS helps). Anyway. Linux is choose your own adventure and not comparable.
For Windows you’re not comparing the same thing. Apple ships a new major OS release on a yearly cadence compared with Microsoft’s 7 years. Some people might prefer Microsoft’s approach. People buying into the Apple ecosystem understand Apple takes a different approach. Also Microsoft isn’t your one stop shop for support. While Windows may be supported for 7 years, i doubt your OEM is supporting your firmware for that long. Apple ties firmware to operating system so that is easier to understand.
