Nope - I get bored of this argument quite quickly. An 'adventurer' can be anyone, and actually, I quite like the idea of playing a rags to riches adventurer who comes from the ordinary folk and makes it big.
The character generation shouldn't just assume that everybody needs inflated stats to become adventurers, and the chargen system should be baselined on establishing typical members of a race. Indeed, there is nothing explicit in the rules that states their stats are inflated because of their 'adventuring' status - it's just a post-mechanic justification.
Even if you get bored of the argument, D&D player characters have never been just anyone.
An OD&D level 1 Fighting Man isn't a farmhand picking up his first sword, he's a Veteran.
No 1st level wizard in any edition has just found out about magic: they're all people who've put in years of study.
Would it be nice to have a system that truly supported zero-to-hero? Yes.
But D&D isn't trying to be that system. At least it generally hasn't, and in the current playtest, does not seem to be.
A first level cleric has a direct line to an actual god, and is able to channel that divinity once per day, as well as casting divine spells. He's either proficient in all weapons and armour, or able to fire off radiant lances at will. He's not the altar boy.
A first level fighter from the playtest already knows how to parry, how to make his strikes deadlier, and at least one other nifty trick. He's trained in the uses of all weapons and armour. He's not the kitchen boy.
A first level thief
cannot fail at hard skill checks in things he's been trained in. Heck, he can't fail at moderate checks in things he hasn't trained in and has a poor natural ability for. He already knows a secret language. He's not Bilbo Baggins, who has never stolen a thing in his life before being hired to be the party thief. He's no first-time pick-pocket.
A first level wizard already knows five spells and three cantrips. He's not the apprentice on his first day.
A first level warlock has already made a pact to gain power. He's not the random scholar who's still considering performing the strange ritual he found in a dusty tome.
A first level sorcerer's power comes from his heritage, so he's intrinsically
not just your average person, even if he didn't already have the ability to cast multiple spells in a day and
and turn his hands into dragon claws.
PCs are clearly not "anyone". They're not the stable boy, the village idiot, the farmhand, or the tavern wench.
Maybe they used to be, but by the time we get our hands on them, they're past that. They're trained. They're intrinsically above average.
