I read on the Cessna 150/152 Restoration FB page that out of the thousands of 152's Cessna built, only about 1,500 (or so) are still airworthy and here in the states.
I guess so many have been wrecked and/or exported that the population has shrunk to this level.
I'm too lazy to research the authenticity of the above but if it's close to being true, the old economic law of supply and demand may be playing and ever increasing role in the value of the 152.
Just throwing this in the mix as food for thought.