Within context that post is sound, the context now is that the 4090 still exists, the 5090 is out soon at a minimum of £2000. is is a wise choice for someone who already had a 4090n from before, which has lost little to no money today?
Probably not
Will the 5090 go the same direction for used values in 2 years too? Probably not either. As someone else said, the 4090n seems to be the new 1080 Ti.
You can't say the hell with the expense then come out with that