If stock A is going to pay a dividend of $1 per share, you are suggesting that the price of the stock is going to be $1 higher than it would have been if there was no dividend? Ok, that's fine. But, then you actually get the $1 paid to you.

If they are including dividends in the returns, then they are talking about total returns, and the formula for a total return is (price + dividend) / (previous price).

If you ever look closely at the claims that the market goes up by an average of 7-10% yearly, you'll see that it always includes dividend reinvestment. Returns are way lower if you don't include the dividends. If you are cash them out as they come, they call that the income return on your investment.

EDIT - I'll also point out that the US returns, according to that source study, are coming from CRSP. CRSP publishes US data according to their own methodology. Chinese data is not coming from them, and there is no reason to believe that it is using the same methodology. Apples v Apples, you know.