Some cameras do hold their valeu a very long time, not 100%, but a lot of it.
F900, EX1, etc. Cameras only lost a ton of value that were SD, and then HD came out. A Red MX is 4K, after all, RAW - it's quite future-proof. It will be an extremely long time before much better than that comes out, and MXs are still used as B Cams on very high end Epic shoots today. Rare is the situation where the MX does not have enough latitude or sensitivity - and never is the situation where it does not have enough resolution.