People in real life are random entities, rarely if ever exactly alike. Rolling for stats merely reflects this in the game.
From the perspective of real life (i.e. assuming people's "ability scores" are drawn from some random distribution) rolling is not necessarily better or worse than point buy. They do have different premises, however.
Rolling is creating a person drawn from that distribution. Point buy is selecting a person from the population with particular characteristics.
Rolling is more like our experience, having not chosen our own stats. If the resonant idea for a player is to see what a random guy can make of his life, this is perfect. See what talents you have and run with them.
Point buy is more like hiring someone for a job: the applicant sees if they want to work there, and hirer sees if the applicant fits what the company wants. If the resonant idea for a player is to play a specific concept, this is perfect. Half-seriously stretching the analogy further: The people with ability scores worse than that allowed by the point buy system either never applied or were dismissed out of hand. The ones who are better are both fundamentally rarer, and if they're that good they probably have sweet NPC jobs anyway.
Either way, point buy merely reflects the self-selection and other-selection aspect of jobs in real life.
One might object that point buy is still artificial: after all, what in the fictional world is equivalent to the "job interview"? If nothing (which I think is likely unless you play the "chosen one"), that would make it a conceit solely for the game, and thus less like "real life". I don't think this is a valid argument, however, because the rolling method makes a similar conceit: whomever we roll turns out to be an adventurer. Picking a random person and getting an adventurer is vanishingly unlikely, barring a truly gonzo setting.
So my point is that both methods represent something from "real life" and both also make a conceit for the sake of the game (though at different times), while serving different inclinations. I think that's wonderful.
I personally enjoy the roll 4d6 drop 1 six times and rearrange method. I've still selected from the random population (which resonates with me), albeit only from the higher ability people who are much more likely to self-select as adventurers. (I'll be embracing the conceit eventually, so why not do it now?) But I also have a lot of freedom to explore various character concepts (as with point buy) to help me scratch my character-building itch. At other times I've randomly selected a valid point buy to fulfill my enjoyment of random with my DM's desire to avoid wide disparity in ability scores. Good times.