On Living a Life Without Meaning

On Living A Life Without Meaning:

Let's assume someone is not religious and does not believe in a Western God or a variation of the Savior myth (or someone is sufficiently skeptical to dismiss the payoff of heaven).

Why would one who does NOT want to A) investigate life with an eye for observation, in an effort to advance human understanding, scientifically and/or technologically, B ) does not want to participate and add anything meaningful to the human conversation with original creations of art, music, literature, or otherwise, C) does not want to procreate in order to add resources and prolong the human experiment and, C) does not, at least, find value in the sensory pleasures of the fruits of man's labor thus far, rich foods, booze and merriment, porn and easy sex, etc., want to go through the motions to sustain life?

It would seem as if that person would just be biding time, meaninglessly working and eating and sleeping and generally trudging about, before they sighed their last breath. It would seem that if, after an honest and thorough evaluation, of course, one were to deem that their life was more work and cost than it was worth and beneficial, would the most efficient and rational course of action, then, be to just, how do you say it nicely, unplug yourself from the game?

We regard the suicidal as irrational and mentally ill, but what about the man who exists with no merit? Wouldn't it be easier for the apathetic to save time? Doesn't it seem much more irrational, instead, to waste 70+ years putting fuel in your body to, not participate, but to watch people, like human isotopes, electrons, and ions, interact and share and grow and (brain) chemically change in this big test tube we inhabit?