* Random rollers (usually) accept that just like in real life some people are simply better than others in lots of ways - we're not all equal-but-different
In real life, you don't get to choose your race, sex, background, or class, but random rollers (usually) still allow this. You also don't get to rearrange your abilities so you can decide what you excel at, but random rollers (usually) allow this too. The conventional randomly-rolled character creation system is not realistic and is not intended to be. It is still, like the standard array and point buy, aimed at allowing players to produce characters of their choice. It simply introduces more variance and allows for some surprises. And I'm not saying that's a bad thing for every player or every group. I myself like surprises, and prefer a normalized random method. But I am urging you to reconsider the validity of this "realism" line of thinking. Unless you yourself do 3d6 in order, roll for race, sex, etc., which is completely fine in its own right, but means you're no longer speaking for what random rollers (usually) do.
Furthermore, if we are to think about realism, let's entertain the idea that a group of adventurers might realistically be closer to equal-but-different than you assert. Adventurers are not a random sample of the population. They're a self-selected elite in an extremely demanding line of work. In terms of abilities, they're probably comparable to a special forces unit or a professional sports team. Yeah, sports teams have some second- and third-stringers, but even those guys are hardly what you'd call "average".
* Random rollers (usually) realize that D&D is to large extent a game of luck both in initial char-gen and in what happens afterwards, and that good luck in the field means far far more in the long run than bad luck during char-gen.
Good luck during char-gen mathematically matters more
in the long run, and increasingly so the longer the long run goes. If Alice rolls an 18 Strength and Bob rolls a 14 Strength, the odds that Bob is going to roll 2 points higher than Alice on every significant Strength attack and check and save and damage roll are small and ever-diminishing as they keep having to make these rolls.
But let's take a step back. Why is it a fact that "D&D is to a large extent a game of luck... in initial char-gen"
which players ought to "realize"
? As has been discussed, even the default character generation rules quite readily allow for a character to be created with no random elements at all. And if they didn't, it would still be the work of moments to homebrew variants that work this way, and the game would still be D&D. It seems here more like you're asserting what you personally want
D&D to be rather than what D&D is
, and that you
ought to realize that D&D is bigger and broader and more open to diverse playstyles than you give it credit for.