It's interesting that #Modern seems to be the single-biggest driver of the MTG secondary market. Changes in meta and legality in Legacy/Standard almost never have any effect on card prices, but changes in Modern are very often met with HUGE swings.
It's making more sense why LOTR was direct-to-Modern, and also why it will likely become the best-selling set ever (usurping Modern Horizons II; a fact which caught me completely off-guard).