I had a feeling in foreseeable near future, there will be a point where Rolex Explorer II prices will shoot up drastically like the GMTs. As people nowadays wanna get into Rolex sport model, their cheapest option will be ExpII around the range of 18K to 23K. Whereby, GMTs and Subs (16710 & 16610) their price point will be around 28K to 30K++ plus.
When the stock of Explorer II starting to dries out, the price will increase to cope with the supplies.
It's just my imaginary prediction. I might be wrong