Seems like roms for emulators are becoming kind of book like. As soon as a new platform reaches market relevance, there is a dash to make sure these old platforms are emulated.

However, rom files specifically (as opposed to executeables for retro computing platforms) seem to be distinctly less fickle in becoming reliably emulateable.

The reason is seemingly simple, the early rom files were essentially an operating system, having all the software required to boot the system included in what now looks like one file.