No one questions the general consensus that P1's IQ4-150 still gives the best (technical) quality images. Definitely a step up from the "second-best" IQ3-100 (which I have) in particular as to fluidity of the photographic process.
But on the other hand, I can understand why some questioning the shelling out of $18K or more on a used electronic device whose market introduction was now more than five years ago that apparently still suffers from various handling gremlins and now also starts running out of factory warranty.
iPhones released before or shortly after the IQ4-150's introduction, iPhone X and iPhone XR, now have an average resale or trade-in value of about $140. Thats 14% of original purchase price. IQ4-150 was about $50K when released, if the same depreciation would apply, would now be $7K!
However, one critical difference is that we now have iPhone 15 but no indication if and when we will see a IQ5.
It always looks to me like you want to down talk the product to get a low-ball price for yourself by trying to "convince" "the forum" that the IQ4 is not worth as much anymore.
The point here is a different one: P1 is still the non-plus-ultra in terms of IQ. It caters to the top 0.1% and these users – enthusiasts with money to spare, pro's and fine art artists – are less sensitive to price and ultimately price is a function of supply and demand.
Supply is low with P1 keeping prices high, demand for its products still being there and sporadic forum sales mostly coming from people exiting the platform due to a) urgent need of cash, b) changing preferences with regards to compactness and functionality.
I would never sell my IQ4 and am awaiting the next gen – could be '25 – to upgrade at 20-25k. The iPhone comparison doesn't make sense – this is a high-end niche product with unmatched specs to this day and it is not like there's anything better out there, even after 5 years. iPhones are mass-market products with gazillion alternatives and incremental upgrades year-on-year. It's not like we have an IQ7 out and you are complaining about the IQ4's second market price being still so high.
Did you see the dynamic range of the Fuji stuff – looks like 14 stops. Blown highlights. IQ4 still unmatched.