Some filmmakers must not be clear about which cameras they used, especially which RED camera. Can you ask the DoP next time, instead of the director?

Yes. a C500 mark ii is right around the corner ;)

There is no Canon 5D mark vi; perhaps you meant mark iv?

The industry is moving in this direction, but not everyone can afford to shoot on IMAX.

These prices are Starting Prices, meaning Brain only. If you want to be able to control the camera (via the monitor), record video (module & SSD are required), power the camera (battery plate & battery are required), mount a lens, etc etc, add at least $6000.00 to every initial brain price, and probably more.
To help justify the high cost of a RED, you will get clients immediately with a RED, but, as with anything, choose the best camera for the project.
I love RED & use them often, mostly for music videos, but have always just rented them. RED's upgrade program is very encouraging for existing RED owners.

How is this "beautifully simple??" The 'Epic' was the 'Brain' and the 'Dragon' was the sensor. Now, the 'DSMC2' (or is it just 'DSMC' or 'DMSC' or 'DSCM?') is the 'brain' and 'Monstro,' 'Helium' and 'Gemini' are the sensors. How is this better or simpler? RED definitely overused the 'Epic' in their product and their website is still very confusing, made worse by throwing in all the upgrades into the main product line. I don't want to look at a Scarlet that only shoots black and white. Just add an "upgrade" button or "click here if you are a current RED owner."
The correct RED naming convention has always been "RED-[brain]-[sensor]." Some have added the resolution at the end in an attempt to add clarity; eg, "RED Weapon Helium 8k." One element that has always added to the confusion is producers or directors talking about their film at panels or at film festivals; they never get it right, but that is really the DoP's job anyway...
I seriously doubt people will name RED cameras correctly in the future with any greater degree of accuracy.