Quoted from Shapeshifter:
Over the next few years most 'red dmd' games will drop in value as they are dated, despite there being some simply awesome titles.
A game's demand is formed by its gameplay reputation (and theme to some extent), not its display. Pins with HD LCDS have now been around since 2011 (WOZ). Demand for classic games has continued to rise. If anything, the DMD era games will continue to rise in value, as their design, code, engineering and QC are leagues beyond the new titles. You don't have to worry about splitting cabinets and chipping clearcoat on older titles.