I'm not too sure that diversity or inclusion has a net cost.
Diversity(tm) and Inclusion(tm) have a cost of inviting Diversity Experts to tell you why you cannot do any of this on your own and why you need to pay them for it, even though none of their materials or solutions have been peer-reviewed and the readily observable effect is that they make everyone miserable.
One is how communities work, the other is how protection rackets work.