There is no known way to create the quantum superpositions at the scale required in an economical way. For all I know, you would need extreme cooling and a vacuum chamber to minimize any and all interference with the outside environment.
Even a little vibration in the system can ruin the whole thing
@cyberia @burnoutqueen In particular, skimming through it for instances of the word "exponential" seems enlightening.
"Exponential" means "this is impossible, forever, with the current approach". It doesn't mean there's not some other approach we don't know exists, but it does mean that continuing on the same path will never get you there.