Is the decline in value with a PC significantly higher than with a game console such as Xbox or Playstation?

Can you agree with that?

Yes. The console prices are limited. The PC prices do not.

Consoles are a practically immutable piece of hardware, you know exactly what you're getting, and it's usable for a long time, even beyond the end of the console cycle.

The problem with PCs is that everyone has their own ideas about the composition, and therefore only addresses a much smaller group of interested parties when selling.