And then;
>Nobody's saying children of farmers or auto-mechanics are any less able. They just don't get the best training.
So it's a meritocracy but the training isn't available to all? Doesn't sound like a meritocracy to me.
Yes, but nothing made out of organized humans ever adheres to mathematically rigorous definition. (1)
Our lot is loads better than that of some poor orphan in Haiti, and our opportunities were distributed with tons more equity. That said, it's far from perfect. There are parts of our messy society that are close to meritocracy, and there's other parts that are headache inducing doppelgangers of it. It's a mess, but you can also think of it as opportunity.
((1) - In fact, whenever you think you are about to make a clever or skeptical point in a societally based intellectual discussion, tell yourself this first, then see if you still want to. Same goes for biology and software engineering.)