You have to leave that mindset about pricing behind. Unless you are going to hold out indefinitely. Because prices will likely remain high for quite some time yet. Heck, there are already credible accusations of chip hoarding to artificially inflate prices.
That Fury is EOL driver support, only has 4GB, and has how many years of hard living left in it? Sell it now, while the price it fetches is way higher than it should be.
And the 6600 can do 1440p smoothly, if you dial in the settings for a particular title. There are a few where it isn't suitable, but those are outliers comparatively. And there are games now, where that Fury runs out of memory at 1080. Selling the Fury and keeping the 6600 is a no brainer from my perspective.