When you only reward merit, you risk increasing education disparity (because, in a nation with liberty, you can't legislate motivation to do well in school). However, you'll notice that, in a nation with liberty, you also can't stop the uneducated from reproducing (and subsequently passing on their negative views of education to future generations). So if you refuse to educate them, you invite a future of an uneducated majority, making uninformed choices.
This is why "reward merit or need" still isn't the right question. The question is "how do we change mindsets to value education." I see the factors to this as including things like: Personal responsibility (so people understand why they will benefit from it), self-worth (so they have the fortitude to endure the struggle)...gotta be plenty more, but I'm improvising here.
Anyhow, the's the rub, when it comes to liberty. You can't make choices compulsory, even when you're certain that it's the wiser choice. Only each individual's personal responsibility can counteract the negative sides of liberty. (Can't legislate personal responsibility either, of course.)
So what do you do? Do your part to spread wisdom. Do your part to spread personal responsibility. But remember, if you want to be an effective teacher, you can't trigger people's defenses. Otherwise you risk perpetuating the very same biases against learning that you're trying to combat.
Endlessly tricky, I admit. Only our perseverance will win out.