The market is strong right now for muscle cars. Everything gets hot and then cools back off. I bought a fastback a year ago to the day. It needs work, but it is a great project. It is already worth 2K more than what i paid for it. I bought it to keep until they bury me in it, but if it goes up in value while i have it.... well then it was a good buy as well as fun.
Personally, I like the fact that these and other cars are getting the attention they deserve. We have seen it in the euro cars for years and they were so overpriced that it was insane. But now, the hot cars are american made muscle cars. A hemi cuda for over 100K. A 67 Shelby for 350K. The list goes on and folks, THAT IS AWESOME!!!
As far as it being out of reach, it is in some cases. You can still buy a decent coupe for under 10K and under 2K if it is rough. Fastbacks and convertibles are higher, but that is simply because they are in more demand and ford made less of them. However, i still see restorable fastbacks sell for less than 2K on ebay every week. Some of them are rough, but they are restorable.
The market will sort itself out. Just ask the guy who bought the t-bucket 20 years ago for a hefty chunk of change...