It's a bit like a long-standing marriage. Each partner already gets the benefits associated with being in the relationship so the only way that they can respond to the suggestion that the marriage should end is to make some forecasts about how things are likely to be after the split - not knowing what the asset split, custody arrangement, alimony and so on are going to be like.
OTOH the Brexit campaign seem to be doing the equivalent of telling the man that he can continue to **** his ex-wife whilst having his pick of other sex partners, that he can spend the money he currently contributes to the running of the family homes on a new stereo, and a new car, and a great holiday and so on, that he'll get full custody of the kids and the dog unless he doesn't want them that weekend in which case his ex-wife will be happy to take them.