The film's trailer came out in September, featuring Spacey looking nearly unrecognizable as Getty:"All the Money in the World" -- costarring Michelle Williams and Mark Wahlberg -- is about the kidnapping of Getty's grandson, with the billionaire reluctant to pay the ransom. (FYI, the 16-year-old grandson is played by Charlie Plummer, but there seems to be no relation to Christopher Plummer.)
Since they aged Spacey and really made him stretch for the role, it does seem like Christopher Plummer could probably step in, skip the hair and makeup transformation, and fill the role of the cold patriarch with ease. This is in his wheelhouse.
Ridley Scott's movie was pulled from the upcoming AFI Fest thanks to the Spacey allegations, and they clearly don't want to be attached to those headlines anymore. So they're erasing him from the film in the eleventh hour. According to Entertainment Weekly, reshoots are expected to begin soon, and even though we're six weeks out, they still plan to release the movie starting Friday, Dec. 22.