Ok apologies. But you get my point, it’s a set of instructions made for actual hardware with built-in samples. I don’t think there’s any such thing in modern computers even beyond emulation on OS level.
Sound players are made to play sound, not instructions, and most people don’t need to play MIDIs. Even so, the actual playback experience then depends on the OS/hardware/whatever, which again is not something you expect from a sound player.
You can always use specific software to play MIDIs, which are better equipped for it with stuff like MIDI font support, instrument selection and other stuff.