I agree that FM broadcasts are not about to vanish anytime soon, but the sale value of FM tuners has declined, particularly for higher end models. There are exceptions, but there are less people chasing the same number of tuners, hence a decline in prices.
From everything I read
It seems like F.M. Radio will be going away in the near future. I currently have a mint Mac tuner that I don't use but it looks nice on the rack. If F.M. Radio does go away as expected do you think the value of this piece will drop like a rock? The only thing the piece has going for it is that it's a vintage Mac piece and there seems to always be a market for vintage Mac gear. On the other hand if it can't be used will people still want it?