Seems to me, some of the Newer Sterns like Turtles and AIQ are turning over a bit. Some games like EHOH and JJP Pirates are rising in price pretty quickly and see to turn over. Some older Sterns such as KISS and GB also seems to be skyrocketing in price and they are also changing hands. The 1990's B/W games seem to be advertised less but when they do they sell fairly quickly also.
I think the non working EM's are getting snapped up as projects. Especially the 1970's wedge heads. Not a lot of financial risk in one of these up front. As long a complete, one can get them working and they are a lot of fun.