I'm not sure how long the older pins from the 90's are going to keep increasing in value (note I am not saying they will decrease) when all these new manufacturers get their pins out (and Stern continues to improve their pins, I think we all agree Stern is spending more money on their pins now, which is good). Eventually, the older pins will start feeling dated and people will gravitate to the newer pins and their prices will rise while the older pins have little movement up or down.
SM and LOTR are going to have big bumps in prices in my opinion.