The motivation was that we've run out of other things to scaremonger about so we'll come up with what Bruce Schneier calls movie-plot threats and go with those instead. The few explosives that are liquid are also incredibly impractical to work with in most cases except for perhaps perchloric acid which is nitrogen-free so won't be detected but then persuading that to detonate from a seat in economy class is going to be quite a feat.

The country I'm in abolished the liquids nonsense for domestic flights (which they can do because it's domestic travel) around a decade ago with the reasoning that it wasn't serving any purpose.