While I agree that ROM + emulator is best for preservation, you absolutely can fix the space invader bug because you have the C code which would let you add in delays. Just like there are many versions of Space Invaders for different consoles an none of them use emulation but play like the original. I'm a fan of si78c, a memory accurate reimplementation of the 1978 arcade game written in C.

Of course Space Invaders wasn't written in C so this new tool doesn't apply.

But the article does talk about how the decompiler sometimes introduces bugs and how they were manually fixed before compiling.

So you were right but the problem you brought up has already been addressed. (And will continue to need to be addressed as more cross compiling bugs are found in each game.)

I interpreted the word "legacy" the OP used as the fandom for old games rather than perfect preservation.