Except caramelized onions aren't caramelized. Or not meaningfully anyway. The color comes from Maillard browning. The sweetness comes from breaking down larger

Except caramelized onions aren't caramelized. Or not meaningfully anyway. The color comes from Maillard browning. The sweetness comes from breaking down larger sugars into smaller, and concentration through evaporation of water. Caramelization products aren't sweet, they're primarily bitter. Sweetness in caramel products comes from residual sugar that hasn't been caramelized.