Emulation is starting to get gaps too... for example, running Windows 95 in an emulator on a modern machine is getting harder and harder (emulators like vmware and virtualbox don't emulate the CPU speed accurately, which causes the system not to boot, and they also don't emulate various paging behaviours of old intel CPU's accurately which causes windows applications to crash within a few seconds of starting).
There are binary patches to windows 95 to fix these issues, but as the system gets older it's less likely people will put effort into binary patching it for compatibility with modern systems. And if it were more obscure, you'd be SOL.