Cant see any price dropping since 2005, so why should it drop in future? The most legendary home gaming system will stay the same.
Worth anything? Certainly worth something. But the price will either rise (unlikely) or fall depending on the people interested and the people selling. I would predict that demand for it will slowly decrease. And people trying to sell it won't be able to get as high of prices for it. Really the high prices right now are just because they don't want to sell for what they can get for it now, they are all waiting for a sucker that will pay the big bucks. Eventually the AES may well be cloned by someone. That may affect the value. Plus anytime SNKP makes available NeoGeo games on other platforms that has an effect. NeoGeo was far more desirable before you could get the games on systems that could handle them well like PS2 and DreamCast. That and more people know about emulation now.
Compared to other systems AES games had tiny print runs, sometimes just a few thousand copies (VIEWPOINT is rumored to have had a print run of just 5000 copies, METAL SLUG most likely around 1000), compared to the quantities Playstation and SNES games were produced in, which often had 100.000 or more copies produced.
And the only reason that would be possible is because the same ROM chips were used in the MVS which is where most of the MaskROMs ended it, in MVS carts. And this is why people do unofficial conversions which are essentially the same thing as AES releases, and apparently in some cases this is exactly what they are.
Indeed, saves tons of money, and as I said it allows for minimal AES/Home Cart release numbers since you don't have any AES specific parts other than the PCBs which are used in many different AES games.