I think you're off by roughly half; an IBM PC with printer and monitor was about $5000 in 80s money, probably more like $10k adjusted

It depends on what range of the years 1981-1984 we're talking about, but yes, it was very costly. Not that a full IBM PC would necessarily be required to write a novel. People were writing whole books on less expensive CP/M based systems with like two 160KB floppy drives. One to boot and run the word processor software from and one for data file storage.

I have a family member who bought an Osborne Portable for something like $1800 1981 money, an inflation calculator says that would be the equivalent of $6,971.17 today.