You could say for just about every electronic, if you waited a year after release you the ps4 for 329 on ebay with gtav and last of us on black Friday samething with every phone they buy it for 700$ day one a year later you can get on ebay 400$ new, I think with the ps4 you take very little loss if you sell yourself and buy at the right time.
Firstly, other product categories having poor value proposition isn't a good defence for wanting console cycles to have the same. As consumers we ought to demand the maximum value proposition, and it seems that lately we're getting less and less of that. Secondly, it's not really fair to compare to mobile phones. As I've said before, for the majority of people, upgrades are subsided by their contracts, which is why supply and demand works in a slightly different way, and why the drop off in value and the relevant cycles work differently.
With PC gamers who upgrade all the time, losing crap loads of money in the process, that again does not make a good comparison, since these are extreme enthusiast gamers who make up a tiny demographic of the market, and who are happy to lose hundreds of dollars each year or two, just to stay on the bleeding edge of technology. That is and never has been the case with console gaming, where value proposition, convenience, and closed platform optimisations have always been at the forefront of incentive.