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?

It easy actual a tuner not a receiver. I really like the way you explained that. Thank you.

Much like obsolete cameras for which film is no longer available, an FM tuner, in a post FM world, would be nothing more than a static display piece. 

I suspect that initially, the value could plummet but in a 100 years, it may be worth some real money. 

Feel better now? 
Within five years that Mac will become just another dust collector. Sad but true!
Just did some research. Norway will shut off FM in 2017. Some other European countries might shut it off in 2022. In US it would take an act of Congress to end FM, and with all the money at stake, especially with smaller markets unable to convert to digital, most think it will be a long long time before the US ends FM radio. On the other hand, I have a Don Scott modified Mac and Luxman and hardly use them anymore. I sold a D Scott modified Sansei and the price was lower than the past.