"Of course "diversity" and "multiculturalism" is good for capitalism: it introduces more choices; it grows the market. But it will never, never, never be anything more than symbolic."
I don't see 'diversity' and 'multiculturalism' as being euphemisms for choice on the market.
I see them as euphemisms for inequality and the division of the world into competing nationalities.
Those are two things that capitalism is unlikely to abolish.
It is convenient for capitalism to make a virtue out of inequality (by calling it diversity).
And it is convenient too to make a virtue out of the division of people along ethnic lines and call it multiculturalism... or divide and rule, as they used to say.