I don't personally support adding cost to a hard-to-find product, but I guess that's supply & demand.
Deals-All-Year (99.9% approval) is selling two Canon EOS-1D X Mark III bodies for $6999, which is $500 over MSRP in the USA.
Some people may not mind paying the extra $500.
This sale is for a grey market item, but you should still be covered by a Canon USA warranty.
This sale does not include the CFexpress card and reader.
Canon EOS-1D X Mark III $6999 (Reg $6499)
BTW- it was bought from Deals all Year !!
As I understand it, the serial number on bodies means they can see which market the body was intended for, but for some reason the serial number on lenses does not give them the same information.
I can also imagine that bodies are far more likely to go wrong than lenses so maybe they are more lenient on lenses.
But without insider knowledge it is all speculation, certainly these comments of Canon gear not being worked on by Canon USA are news to me who has previously used their services for non USA purchased warranty work.
Firmware for the Canon EOS-1D X Mark III coming in early April to address issue