I paid $4,700 for mine a few months after they were out via CPW, got the free CFast cards and readers too. If the 1DX MkIII is $5,000 after a. few months and I can get $3,000 for my MkII's the 'investment' is closer to $2,.000 than $6,000.
If I move on a high resolution R's' the body will be $3,500+ and the two lenses I'd want, the RF 85 and the RF 35 add another $3,000, then there is yet another $1,000 in adapters for the ND filter and the CPL to use the EF glass I need to use, and then there is the version with the control ring. I'm looking at well over $7,000 to make a serious move on the R's'...