Then should we consider Windows or other commerical software for anything designed to outlast a 5 year period?
Which is why nobody uses MacOS in production for anything but end user devices.
> old Linux kernels neither
They do. All major enterprise distributions backport drivers exactly for that reason – and unlike with Windows, you can update the kernel in place without having to touch any other part of your software stack. Your software won't care whether it's running on top of Linux 2.4 or 4.2, but it will care whether it's running on Windows 7 or Windows 10.