As others have mentioned, the player at the high-end of explorations are subject to the mercy of RNG on success, relic point spread at the end of the week will probably follow a normal bell curve. The primary question then would be what percentage of the bell curve reaches 120 and 160 relics respectively, after accounting for all the failed explorations? That is still a hard unknown.
I expected the "wall" for players to hit in explorations to at clearing the 80 relic mark, and it's not there. Maybe at around 100 relics then or perhaps 120 (I severely doubt it's farther back than 120). Although, if the "wall" is that far back, then that would indicate that Gumi wants/expects most players to at least reach 120 relics. That makes sense in a way, because it is easier to rationalize spending to reaching the grand prize in an event rather than the second prize in that event.