I think part of it is because whether anyone wants to admit it or not, the ISF is sort of iconic, at least for Lexus people. Not as much as an LFA but it still holds its own. The ISF also doesn't have the predator
mouth on it, so by some it might be considered the pinnacle before the body styling change, etc. I am thinking the prices stay high because people don't want to get rid of those cars. Lexus vehicles
generally don't induce the "zomg I cant afford to fix this thing" stuff when you hang onto them used. That means eventually, every ISF, RCF, GSF, finds a home and it stops moving int he marketplace. Unlike a lot
of BMWs, Audis and others that blow up 48 times and get sold a half dozen times because every successive owner gets sick of the BS.

-Mike

I’ve been noticing this as well. I work at a Lexus dealership and IS-F’s are extremely desirable for us. We’ve only had one in the past few years, where as we can’t move our current used RC-F’s. The GS-F and IS-F seem to be more desirable on the used market.

My mom is looking at getting an RC-F and I was surprised by how much the prices have dropped in some cases. The 2015 RC-F is close in price to the 2012-2014 IS-F. I was considering an IS-F for myself if I don’t find an affordable NA MKIV Supra, but I may go for the RC-F instead.